Question

Tim has a picture frame that is 30 cm long and 24 cm wide. He wants to make a picture frame that is similar in shape but is 18 cm long. How wide should this second picture frame be?

Answer 1

30 - 24 = 6
18 - 6 = 12
12 cm wide

Answer 2

We can set up a proportion to find the same shape.

30/24 = 18/x

x stands for how wide in cm.

30/24 = 18/x

Cross multiply

30*x = 30x
24*18 = 432

432 = 30x

30x/30 = 432/30

x= 14.4

Answer: The width should be 14.40 cm wide.