IXL | Relationship between area and perimeter: find the perimeter

The rectangles below have the same area.

3 mi

8 mi

4 mi

What is the perimeter of the orange rectangle?

miles

ref_doc_title.

Learn with an example

question

The rectangles below have the same area.

5 km

6 km

3 km

What is the perimeter of the purple rectangle?

kilometers

key idea

Rectangles with the same area can have different perimeters.

solution

Find the area of the red rectangle.

5 × 6 = 30

Both rectangles have an area of 30 square kilometers. Find the missing side length of the purple rectangle.

You know that one of the sides is 3 kilometers long. Divide the area by 3 to find the missing side length.

30 ÷ 3 = 10

The purple rectangle is 10 kilometers by 3 kilometers. Find its perimeter.

10 + 3 + 10 + 3 = 26

The perimeter of the purple rectangle is 26 kilometers.

Looking for more? Try these:

Lesson: Perimeter

Lesson: Area of rectangles

$Confetti$

Excellent!

Now entering the Challenge Zone—are you ready?

Questions
answeredQuestions

Time
elapsedTime

hr	min	sec
00	00	06

SmartScore
out of 100
IXL's SmartScore is a dynamic measure of progress towards mastery, rather than a percentage grade. It tracks your skill level as you tackle progressively more difficult questions. Consistently answer questions correctly to reach excellence (90), or conquer the Challenge Zone to achieve mastery (100)! Learn more

Teacher tools

Work it out

Not feeling ready yet? These can help:

OO.11Find the missing side length of a rectangle

PP.2Perimeter of rectangles

Lesson: Perimeter

Lesson: Area of rectangles

Excellent! You got that right!

Jumping to level 1 of 1

Excellent!