The ratio of the sides of a rectangle is 3:5. If the perimeter of the rectangle is 40, what is the length of the longer side?

The ratio of the sides of a rectangle is 3:5. If the perimeter of the rectangle is 40, what is the length of the longer side?

Explanation
The ratio of the sides is 3:5, so let's assume the sides are 3x and 5x.
The perimeter of a rectangle is the sum of all its sides:
Perimeter = 2(Length + Width)
= 2(3x + 5x)
= 2(8x)
= 16x
Given that the perimeter is 40:
16x = 40
Divide both sides by 16:
x = 2.5
Now that we have x, we can find the length of the longer side (5x):
Length of longer side = 5x
= 5(2.5)
12.5