Algebra & Trigonometry
posted by Ruth Joy on .
A slice of thickness 1 cm is cut off from one side of a cube. If the volume of the remaining figure is 180 cubic centimeter, how ling is the edge of the original cube
If the original cube had side s, then the volume was s^3.
A 1-inch slab has volume s^2.
So, we know that s^3 - s^2 = 180
s^3 - s^2 - 180 = 0
Inspection reveals that s=6 is one answer. So, now we have
(s-6)(s^2 + 5s + 30)
The quadratic has no real roots, so s=6 is the only answer.