IXL | Relationship between area and perimeter

The rectangles below have the same perimeter.

9 in

7 in

What is the area of the orange rectangle?

square inches

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Learn with an example

question

The rectangles below have the same perimeter.

2 in

5 in

1 in

What is the area of the gray rectangle?

square inches

key idea

Rectangles with the same perimeter can have different areas.

solution

Find the perimeter of the pink rectangle.

2 + 5 + 2 + 5 = 14

Both rectangles have a perimeter of 14 inches. Find the missing side length of the gray rectangle.

You know that two sides of the gray rectangle are 1 inch long. Subtract from the perimeter to find the combined length of the other two sides.

14 − 1 − 1 = 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 gray rectangle is 6 inches by 1 inch. Find its area.

6 × 1 = 6

The area of the gray rectangle is 6 square inches.

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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