Question

find the perimeter of a triangle if one side is 28 feet , another side is four-ninth the perimeter , and the third side is two-fifth the perimeter.

Answer 1

Assume that the perimeter is x
x = 28 + (4/9)x + (2/5)x
x(1 - 4/9 - 2/5) = 28

Solve the calculation above, and you'll get the answer

Answer 2

560 feet