Finding Dimensions of Rectangles

This lesson teaches how to find the base or height of a rectangle using its perimeter. It begins with an introduction to the concept, followed by examples demonstrating how to calculate the height when the base and perimeter are known, and vice versa. The lesson also includes tips for performing these calculations quickly in your head, with additional examples to reinforce the learning.

What is the formula to find the height of a rectangle if you know its perimeter and base?

• Subtract the perimeter from the base

• Multiply the perimeter by 2 and add the base

• Add the perimeter and base, then divide by 2

• Divide the perimeter by 2 and subtract the base

If a rectangle has a perimeter of 10 and a base of 3, what is its height?

• 4

• 1

• 2

• 3

How do you find the base of a rectangle if you know its perimeter and height?

• Divide the perimeter by 2 and subtract the height

• Multiply the perimeter by 2 and add the height

• Subtract the perimeter from the height

• Add the perimeter and height, then divide by 2

A rectangle has a perimeter of 18 and a height of 5. What is its base?

• 6

• 3

• 4

• 5

What is the first step in quickly calculating the base of a rectangle mentally?

• Subtract the height from the perimeter

• Divide the perimeter by 2

• Multiply the perimeter by 2

• Add the height to the perimeter

For a rectangle with a perimeter of 22 and a height of 4, what is the base?

• 5

• 6

• 7

• 8

If a rectangle has a perimeter of 30 and a base of 9, what is its height?

• 5

• 7

• 6

• 8