Percent of Change of Dimensions

Percent of Change of Dimensions

Formulas

• Dilation: Percent of original=100% + percent of increase

• Reduction: Percent of original=100% - percent of decrease

One square is 50% larger than another square

a. The perimeter of the larger square is what percent of the perimeter of the smaller square?

Dilation: 100% + percent of increase

100% + 50%

So the perimeter of the larger square is 150% or 1.5 times larger

One square is 50% larger than another square

• The area of the larger square is what percent of the area of the smaller?

• Use area formula with new side lengths

• (1.5)² =2.25

The towel shrunk 10% when it was washed. The area of the towel was reduced by what percent?

Reduction= 100% - percent of decrease

To find new area:

• 100 - 10=

• Change percent to decimal .9

• Use area formula (.9)(.9)

• 100 - 81=

• Therefore towel reduced by 19%

If the dimension of a cube are increased 100%, by what percent is the volume increased?

Volume: length x width x height

Increase by 100% means each measure is doubled

Therefore the 1inch is now 2 inches

New volume: 8

8 x 100

Meaning the new is 800% larger

Increase would be 800 = 100 + ?

? is 700

Multiple Choice

Becky reduced the size of the image on the computer screen by 40%. By what percent was the area of the image reduced?

• 60 %

• 64 %

• 36 %

Multiple Choice

Renaldo increased the image size on the computer screen by 20%. By what percent did the area of the image increase?

• 120 %

• 44%

• 144%