Answer:
The length of the sides are 19 feet, 24 feet and 38 feet
Explanation:
Let x represent the length of the first side of the triangle.
Let y represent the length of the second side of the triangle.
Let z represent the length of the third side of the triangle.
One side of a triangle is 2 times the second side. Assuming it is the first side of the triangle that is 2 times the second side. It means that
x = 2y
The third side is 5 feet longer than the second side. It means that
z = y + 5
The perimeter of a triangle is 81 feet. It means that
x + y + z = 81 - - - - - - - - - 1
Substituting x = 2y and z = y + 5 into equation 1. It becomes
2y + y + y + 5 = 81
4y = 81 - 5 = 76
y = 76/4 = 19
z = y + 5 = 19 + 5 = 24
x = 2y = 2×19 = 38