Question

the sides of a triangle are in the ratio 5 : 12 : 13. what is the length of each side of the triangle if the perimeter of the triangle is 15 inches?

Answer 1

The ratio would add up to a perimeter of 30, so your perimeter is 15; each side will be in the same ratio of 1:2
5* 1/2 = 2.5 inches
12 * 1/2 = 6 inches
13 * 1/2 = 6.5 inches

2.5 + 6 + 6.5 = 15 inches.
(This does check)

Answer 2

use the unitary method to find the value of 1 part in the ratio.

start with adding the parts in the ratio.... 5 + 12 + 13=

the divide the perimeter by the total number of parts

I unit = 15/total parts

lastly, multiply each value in the ratio by the value of 1 unit

hope it helps