IXL | Relationship between area and perimeter

The rectangles below have the same perimeter.

5 km

3 km

4 km

What is the area of the orange rectangle?

square kilometers

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Learn with an example

question

The rectangles below have the same perimeter.

5 m

9 m

8 m

What is the area of the orange rectangle?

square meters

key idea

Rectangles with the same perimeter can have different areas.

solution

Find the perimeter of the green rectangle.

5 + 9 + 5 + 9 = 28

Both rectangles have a perimeter of 28 meters. Find the missing side length of the orange rectangle.

You know that two sides of the orange rectangle are 8 meters long. Subtract from the perimeter to find the combined length of the other two sides.

28 − 8 − 8 = 12

So, the combined length of the two other sides is 12. Divide by 2 to find the length of each of those sides.

12 ÷ 2 = 6

The orange rectangle is 6 meters by 8 meters. Find its area.

6 × 8 = 48

The area of the orange rectangle is 48 square meters.

Looking for more? Try these:

Lesson: Rectangles

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II.8Rectangles with the same perimeter or area

Lesson: Rectangles

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