Question

The triangle has a perimeter of 65 feet. What are the
lengths of sides l, m, and n?

Answer 1

• l = 10 feet
• n = 25 feet
• m = 30 feet

Explanation:

The perimeter of a triangle with sides l=m/3, n=l+m-15, and m is 65 feet. You want to know the lengths of the sides.

Perimeter

The perimeter is the sum of the side lengths.

P = l +m +n

P = (1/3)m +m +(l +m -15) = (1/3)m +m +(1/3)m +m -15

65 = 8/3m -15 . . . . . simplify, use P=65

80 = 8/3m . . . . . . . . add 15

30 = m . . . . . . . . . . . multiply by 3/8

Then the other sides are ...

l = 1/3m = 1/3(30) = 10

n = l +m -15 = 10 +30 -15 = 25

The lengths of the sides are l = 10 ft, n = 25 ft, m = 30 ft.