I FOUND YOUR FULL QUESTION IN OTHER FUENETES.
PLEASE SEE ATTACHED IMAGE.
For this case what you should do is find the area of the triangle which will be given by:
A = (1/2) * (b) * (h)
Where
b: base
h: height
Substituting the values we have:
A = (1/2) * (25 1/2) * (15)
A = 191.25 feet ^ 2
Answer:
she will need 191.25 feet ^ 2 to cover the back of the cabin
