Arectangular box with a volume of 784 ft3 is to be constructed with a square base and top. the cost per square foot for the bottom is 15¢, for the top is 10¢, and for the sides is 1.5¢. what dimensions will minimize the cost

I think it is 15 so I don’t know that if it right

In the first triangle 80+20+p=180 (since sum of all angles of a triangle is 180)so p= 80also in second triangle 55+45+q=180 (since sum of all angles of a triangle is 180)so q=80so we can conclude that p=80 degrees q=80 degrees so p=q=80 degreeshence option b is correct