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how do you find the area of similar polygons

by Candido Balistreri Published 2 years ago Updated 2 years ago
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The area ratio of two similar polygons is equal to the square of the proportion of any two corresponding sides and two corresponding diagonals. A L / A s = (S L /S S) 2 A L / A s = (d L /d S) 2

If two polygons are similar, then the ratio of their areas is equal to the squares of the ratios of their corresponding side
corresponding side
In geometry, the tests for congruence and similarity involve comparing corresponding sides and corresponding angles of polygons. In these tests, each side and each angle in one polygon is paired with a side or angle in the second polygon, taking care to preserve the order of adjacency.
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Jan 14, 2019

Full Answer

How do you find the missing area of a polygon?

Area: Multiply the square of the scale factor by the known area to find the missing area. Similar Polygons: When two polygons are similar, their corresponding angles are congruent, and their corresponding side lengths have the same ratio. Scale Factor: The ratio of the corresponding side lengths.

How do you find similar polygons?

Similar polygons are polygons whose corresponding angles are congruent, and whose lengths of corresponding sides are proportional. The idea of similarity of triangles can easily be extended to that of n-sided polygons, for n > 3. Similar polygons are polygons whose ratio of the perimeters is equal to the scale factors of the two polygons.

How do you find the scale factor of similar polygons?

To find the scale factor, we simply create a ratio of the lengths of two corresponding sides of two polygons. If the ratio is the same for all corresponding sides, then this is called the scale factor and the polygons are similar.

How do you use similar figures to find the area?

How Do You Use Similar Figures to Find the Area of a Polygon? When you're working with similar figures, knowing the scale factor can help you find all sorts of pieces including side measurements and area. This tutorial shows you how to use the scale factor to help find the area of one of the figures. How Do You Find the Area of a Rectangle?

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How do you find similar polygons?

Two polygons are similar if their corresponding angles are congruent and the corresponding sides have a constant ratio (in other words, if they are proportional). Typically, problems with similar polygons ask for missing sides. To solve for a missing length, find two corresponding sides whose lengths are known.

How do you find the area of two similar polygons?

If you know the scale factor of two similar polygons, you can find the perimeter of the second polygon by multiplying the perimeter of the first polygon by the scale factor. The area of the second polygon is found by multiplying the area of the first polygon by the scale factor squared.

How do you find the area of a polygon?

5:076:55How to Calculate the Area of Polygons - YouTubeYouTubeStart of suggested clipEnd of suggested clipThe area of a polygon is one-half times the perimeter. Times the height or the apothem.MoreThe area of a polygon is one-half times the perimeter. Times the height or the apothem.

How do you find area of similarity?

0:088:58Similar Shapes: Areas - YouTubeYouTubeStart of suggested clipEnd of suggested clipSo 2 times 5 the area for this rectangle will be 10 centimeters squared and therefore this one is 4MoreSo 2 times 5 the area for this rectangle will be 10 centimeters squared and therefore this one is 4 times 10 which is 40 centimeters squared so as you can see the areas are four times bigger.

How do you find the missing side of a similar polygon?

1:477:55How to Find the Missing Side of a Similar Shape - YouTubeYouTubeStart of suggested clipEnd of suggested clipSo six times X is 6x 4 times 15 is 60. Now we have a nice easy one-step equation. So our missingMoreSo six times X is 6x 4 times 15 is 60. Now we have a nice easy one-step equation. So our missing side would be 10 10 meters. If we look at the next example the ratio of this triangle is 40 to 45.

How do you find the area of similar triangles?

2:205:10Area of Similar Triangles - YouTubeYouTubeStart of suggested clipEnd of suggested clipWe have if two triangles are similar then the ratio of their areas is the square of the ratio ofMoreWe have if two triangles are similar then the ratio of their areas is the square of the ratio of their sides.

What are the areas of both polygons?

Area of a polygon is the region occupied by a polygon. Polygons can be regular and irregular. The basic polygons which are used in geometry are triangle, square, rectangle, pentagon, hexagon, etc....Area of Polygon Formulas.Name of the PolygonArea FormulaTriangle1/2 × base × heightSquareside2Rectanglelength × width3 more rows

What is the formula for a polygon?

Polygon Formula The important polygon formulas are: The sum of interior angles of a polygon with “n” sides =180°(n-2) Number of diagonals of a “n-sided” polygon = [n(n-3)]/2. The measure of interior angles of a regular n-sided polygon = [(n-2)180°]/n.

How do you find the area of a polygon with side lengths?

1:302:15Find Area of Regular Polygon Given Side Length - YouTubeYouTubeStart of suggested clipEnd of suggested clipSo the base is 20 times the height which is 10 square root of 3. And then all we have to do isMoreSo the base is 20 times the height which is 10 square root of 3. And then all we have to do is multiply by 6 since we have 6 of these triangles. So we're gonna multiply by 6.

How do you find the area and perimeter of similar figures?

4:2322:51Perimeter and Area Ratios of Similar Figures - YouTubeYouTubeStart of suggested clipEnd of suggested clipThat's just something multiplying by the scale factor of two similar figures same shape. But mayMoreThat's just something multiplying by the scale factor of two similar figures same shape. But may vary in size is a over B then the ratio of the perimeters is a over B.

How do you find the scale factor of similar polygons?

To find the scale factor, we simply create a ratio of the lengths of two corresponding sides of two polygons. If the ratio is the same for all corresponding sides, then this is called the scale factor and the polygons are similar.

Do Similar figures have the same area?

Similar triangles will have the ratio of their areas equal to the square of the ratio of their pair of corresponding sides. So, the areas of two triangles cannot be necessarily equal. But note that congruent triangles always have equal areas.

How do you find the scale factor of two similar polygons?

How To Find Scale Factor? To find the scale factor, we simply create a ratio of the lengths of two corresponding sides of two polygons. If the ratio is the same for all corresponding sides, then this is called the scale factor and the polygons are similar.

How are the areas of two similar figures related?

If two polygons are similar, the ratio of their areas is equal to the square of the ratio of their corresponding sides.

What is the ratio of two similar polygons?

In similar polygons, the ratio of one side of a polygon to the corresponding side of the other is called the scale factor. The ratio of all parts of a polygon (including the perimeters, diagonals, medians, midsegments, altitudes) is the same as the ratio of the sides.

How to find the area of a rectangle?

To find the area of a rectangle, multiply the length times the width! This tutorial will show you how to find the area of a rectangle. Check it out!

How to square a number?

Want to square a number? Just take the number and multiply it by itself! If you square an integer, you get a perfect square! Check out squaring in this tutorial!

Why are proportions considered equations?

The idea of proportions is that a ratio can be written in many ways and still be equal to the same value. That's why proportions are actually equations with equal ratios. This is a bit of a tricky definition, so make sure to watch the tutorial!

Area and Perimeter of Similar Polygons

Polygons are similar when the corresponding angles are equal and the corresponding sides are in the same proportion. The scale factor for the sides of two similar polygons is the same as the ratio of the perimeters.

Examples

Two trapezoids are similar. If the scale factor is \begin {align*}\frac {3} {4}\end {align*} and the area of the smaller trapezoid is \begin {align*}81 \ cm^2\end {align*}, what is the area of the larger trapezoid?

Review

Determine the ratio of the areas, given the ratio of the sides of a polygon.

Review (Answers)

To view the Review answers, open this PDF file and look for section 10.7.

How to find the missing side length?

Side length: Multiply the scale factor by the corresponding side to the missing side length.

How to find scale factor?

When two polygons are similar, you can determine the scale factor by finding the ratio of any pair of corresponding sides. If quadrilateral {eq}ABCD {/eq} is similar to quadrilateral {eq}EFGH {/eq}, choose any pair of corresponding sides and find the ratio.

What is the area of two similar polygons?

The area of two similar polygons is 120 cm 2 and 30 cm 2. If a side of the smaller polygon has a length of 3 centimeters, find the length of the corresponding side of the larger polygon.

What is similarity in polygons?

Similar polygons are polygons whose corresponding angles are congruent, and whose lengths of corresponding sides are proportional. The idea of similarity of triangles can easily be extended to that of n-sided polygons, for n > 3. Similar polygons are polygons whose ratio of the perimeters is equal to the scale factors of the two polygons.

How to find scale factor of parallelogram PQRS to JKLM?

To obtain the scale factor of parallelogram PQRS to JKLM, divide the perimeter of PQRS, which is 94 centimeters, to the circumference of JKLM, which is 18.8 centimeters.

How many units are in the perimeter of PQRS?

The perimeter of PQRS is 74.6 units.

What is the area ratio of two similar triangles?

In similar triangles, the ratio of the areas is equal to the square of the ratio of the corresponding sides. The same goes with two similar polygons for n > 3. The area ratio of two similar polygons is equal to the square of the proportion of any two corresponding sides and two corresponding diagonals.

How many square units are in a larger polygon?

The area of a larger polygon is 45 square units.

How many centimeters is the length of the corresponding side of the larger polygon?

The length of the corresponding side of the larger polygon S L is equal to 6 centimeters.

How to find the area of a polygon?

To find the area of a regular polygon, all you have to do is follow this simple formula: area = 1/2 x perimeter x apothem. Here is what it means: Perimeter = the sum of the lengths of all the sides. Apothem = a segment that joins the polygon's center to the midpoint of any side that is perpendicular to that side.

How to find the area of a square?

Find the area of a square. To find the area of a square, just square the length of one side. This is really the same thing as multiplying the base of the square by its height, because the base and height are the same. If the square has a side length of 6, then the area is 6 x 6, or 36.

How to make an array of coordinates?

Create an array. List the x and y coordinates of each vertex of the polygon in counterclockwise order. Repeat the coordinates of the first point at the bottom of the list.

How to find the perimeter of a hexagon?

You know that x = half the length of the bottom side of the triangle. Double it to get the full length. The bottom side of the triangle is 20 units long. There are six of these sides to the hexagon, so multiply 20 x 6 to get 120, the perimeter of the hexagon.

What is the area of a trapezoid?

The area is simple [ (6 + 8) x 10]/2, which can be simplified to (14 x 10)/2, or 140/2, which makes for an area of 70.

How many square centimeters are there in a 7 cm radius?

Part 3 above has nothing to do with circles. Any circle with a 7 cm radius has an area of 49π or 153.937 square centimeters.

What is the area of a square?

If the square has a side length of 6, then the area is 6 x 6, or 36.

What does it mean when two polygons are similar?

This means that if two polygons are similar, then their corresponding angles are congruent but their their corresponding sides are proportional as displayed in the figure below .

Why are congruent polygons the same size?

As you may recall, congruent polygons have the exact same size and are a perfect match because all corresponding parts are congruent (equal). Whereas, similar polygons have the same shape, but not the same size (i.e., one is bigger than the other).

How To Find Scale Factor?

To find the scale factor, we simply create a ratio of the lengths of two corresponding sides of two polygons. If the ratio is the same for all corresponding sides, then this is called the scale factor and the polygons are similar.

What is the scale factor of a polygon?

We need a scale factor! If two polygons are similar, then the ratio of the lengths of any two corresponding sides is called the scale factor. This means that the ratio of all parts of a polygon is the same as the ratio of the sides.

What is the scale factor of two quadrilaterals?

The above example indicates that the scale factor for the two quadrilaterals is 3/2 and proves that the two polygons are indeed similar.

What is similar polygon?

Similar polygons definition. On the other hand, In Similar polygons, the corresponding angles are congruent, but the corresponding sides are proportional. So, similar polygons have the same shape, whereas their sizes are different. There would be certain uniform ratios in similar polygons.

When are two polygons similar?

Two polygons are similar when the corresponding angles are equal/congruent, and the corresponding sides are in the same proportion.

What is the ratio of all sides of a square?

All sides of a square are equal. If let’s say, square1 has a side length equal to ‘a’ and square2 has a side length equal to ‘b’, then all the corresponding sides' ratios will be the same and equivalent to a/b. Hence, all squares are similar squares.

How to tell if two rectangles are similar?

Two rectangles are similar when the corresponding adjacent sides have the same ratio. We do not need to check the angles as all angles in a rectangle are 90 degrees. In the above image, the ratios of the adjacent side are . Hence, these are similar rectangles.

What is the similarity of squares?

Let us discuss the similarity of squares. According to the similarity of quadrilaterals, the corresponding angles of similar quadrilaterals should be equal. We know that all angles are 90 degrees in the square, so all the corresponding angles of any two squares will be the same. All sides of a square are equal.

How are two quadrilaterals similar?

Two quadrilaterals are similar quadrilaterals when the three corresponding angles are the same ( the fourth angles automatically become the same as the interior angle sum is 360 degrees), and two adjacent sides have equal ratios.

What are the concepts of similarity and congruence?

This article discussed the concepts of similarity in polygons looking at some specific cases of similar quadrilaterals like similar squares, similar rectangles, and similar rhombuses.

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Steps to Find Side Lengths, Perimeters, and Areas of Similar Polygons

  • Step 1:Determine corresponding sides of the similar polygons by looking at the names of the polygons. The first named point in the first polygon corresponds to the first-named point in the second polygon, and so on. For example, if quadrilateral {eq}ABCD{/eq} is similar to quadrilateral {eq}EFGH{/eq}, then: 1. {eq}\angle{A}{/eq} corresponds to {eq}...
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Definitions For Similar Polygons

  • Similar Polygons:When two polygons are similar, their corresponding angles are congruent, and their corresponding side lengths have the same ratio. Scale Factor:The ratio of the corresponding side lengths. So, let's try using these definitions to find side lengths, perimeters, and areas of similar polygons in the following three examples! First, we'll look at an example of finding a side …
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Example Problem 1 - Finding The Side Length

  • Pentagon {eq}ABCDE{/eq} is similar to pentagon {eq}FGHJK{/eq}. What is the length of side {eq}JK{/eq}? Step 1:Side AB corresponds to side {eq}FG{/eq}, side {eq}BC{/eq} corresponds to side {eq}GH{/eq}, side {eq}CD{/eq} corresponds to side {eq}HJ{/eq}, side {eq}DE{/eq} corresponds to side {eq}JK{/eq}, and side {eq}EA{/eq} corresponds to side {eq}KF{/eq}. Step 2:Use sides {eq}BC{…
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Example Problem 2 - Finding The Perimeter

  • Pentagon {eq}ABCDE{/eq} is similar to pentagon {eq}FGHJK{/eq}. What is the perimeter of pentagon {eq}FGHJK{/eq}? Step 1:Side {eq}AB{/eq} corresponds to side {eq}FG{/eq}, side {eq}BC{/eq} corresponds to side {eq}GH{/eq}, side {eq}CD{/eq} corresponds to side {eq}HJ{/eq}, side {eq}DE{/eq} corresponds to side {eq}JK{/eq}, and side {eq}EA{/eq} corresponds to side {eq}…
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Example Problem 3 - Finding The Area

  • Pentagon {eq}ABCDE{/eq} is similar to pentagon {eq}FGHJK{/eq}. The area of pentagon {eq}ABCDE{/eq} is {eq}172\ \mathrm{sq.\ units}{/eq}. What is the area of pentagon {eq}FGHJK{/eq}? Step 1:Side {eq}AB{/eq} corresponds to side {eq}FG{/eq}, side {eq}BC{/eq} corresponds to side {eq}GH{/eq}, side {eq}CD{/eq} corresponds to side {eq}HJ{/eq}, side {eq}DE{…
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1.Videos of How Do You Find the Area of Similar Polygons

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