Word Problem - College Level

The perimeter of a triangle is 20 inches. If the medium side is 5 inches more than the shortest side and the longest side is 3 times the shortest side, find the dimensions for all the sides?

Answer: S = 3 inches , M = 8 inches , L = 9 inches

Explanation:

To solve this problem we use the following variables:
S = shortest side
M = medium side
L = longest side
P = Perimeter

We know that the perimeter equals the sum of the three sides therefore:
P = L + M + S

Now we plug in our numbers from the problem:
P = 20
M = (5 + s)
L = 3s

20 = (5+s) + 3s + s
20 = 5 + 5s
20 – 5 = 5s
15 = 5s
s = 15/5 = 3

Now we know that the shortest side = 3 inches. We use this value to find the other sides as follows:

M = (5 + 3) = 8 inches
L = (3) (3) = 9 inches

In order to check it we add the values as follows:

P = 9 + 8 + 3 = 20 inches

©Copyright 2007.Najwa S. Hirn. All rights reserved.