V = (1/2) area of cross-section times length.
Note: I will use L in place of x to represent the length of the prism.
In short, V = (1/2)*b*h*L.
To find the surface area, use
A = bh + 2Ls + Lb
Volume given to be 15, 510.
Part (a) set up:
15, 510 = (1/2)(60)(11)L
Can you finish? Just solve for L to find your x-value.
Part (b) set up:
To answer part (b), you must find the value of L in part (a).
A = (60)(11) + 2L(61) + L(60)
Understand? Take it from here.
