Question

The length of a rectangle is six times its width.

If the area of the rectangle is 600 in, find its perimeter.

Answer 1

140 in

Explanation:

x = length

y = width

x = 6y

area = x × y = 600 in² (I hope you forgot to put the ² on the in and not your teacher).

perimeter = 2x + 2y

using the first equation as substitute in the second equation we get

6y × y = 600

6y² = 600

y² = 100

y = 10 in

x = 6y = 6×10 = 60 in

perimeter = 2×60 + 2×10 = 120 + 20 = 140 in