Answer:
l = 10 feet
m = 30 feet
n = 25 feet
Total Perimeter = 65 feet
Explanation:
The perimeter of a trianlge is the sum of its three sides, and in this case is equal to 65 feet.
65 feet = l + m + n
l + m + n = 65
We also know that:
l = (1/3)m, and
n = l+m-15
Substitute these definitions of l and n into the original equation:
l + m + n = 65
[(1/3)m] + m + [l+m-15] = 65
[(1/3)m] + m + [[(1/3)m]+m-15] = 65
Simplify:
(1/3)m + m + (1/3)m + m - 15 = 65
2m + (2/3)m = 80
(6/3)m + (2/3)m = 80
(8/3)m = 80
m = 80*(3/8)
m = (10)*(3)
m = 30 feet
Since l = (1/3)m, l = 10 feet
Since n = l+m-15, n = 10 + 30 - 15, or 25 feet
The three sides are
l: 10 feet
m: 30 feet
n: 25 feet
Total = 65 feet