Cube and sphere volume and surface area problem

[jthwengen]

What is side lenght of a cube whose volume is equal to its surface area


What is the radius length of a sphere whose volume is equal to its surface area

 

[galactus]

What is side lenght of a cube whose volume is equal to its surface area

The volume of a cube is \(\displaystyle V=x^{3}\)

The surface area is \(\displaystyle S=6x^{2}\)

set them equal and solve for x.

What is the radius length of a sphere whose volume is equal to its surface area

The volume of a sphere is \(\displaystyle V=\frac{4}{3}{\pi}r^{3}\)

Surface area is \(\displaystyle S=4{\pi}r^{2}\)

as with the first one, set them equal and solve for r.