Answer:
The sides would be: Length: 80 | Width: 120
Explanation:
Basically, you know that L = W + 40. (Because length is 40 more than width)
and the perimeter of any triangle is 2L+2W.
In this case, the equation would be 2L + 2W = 400 | (perimeter is 400)
We also know that L = W + 40, so we substitute this equation as L in the above equation, to get 2(W+40) + 2W, which simplifies to 4W+80=400.
Solve, and we get W = 120. Subtract 40 to get length (120-40=80) so
L = 80 | W = 120