How do I find x with these rectangles?

Question

rectangle one: L: 2 in. W: 7 in.

rectangle two: L: 5 in W: x

Answer 1

For this problem I would use proportions,

Since you have the length and width of the first rectangle you can relate that to the length and width of the second rectangle as follows:

2 = 5

7 x

Cross multiply (2*x and 5*7) to get the following:

2x = 7(5) (multiply)

2x = 35 (Divide each side by 2 to solve for x)

x = 17.5

so the width of the second rectangle is 17.5 in or 18 in if you are asked to round to the nearest whole number.