The cube of a means we raise a to the 3rd power:

a^3

The 4th power of B means we raise b to the 4th power:

b^4

Varies directly means there exists a constant k such that:

C = ka^3

Also, varies inversely means we divide by the 4th power of B

C =

**ka^3/b^4**

Varies

*directly*as means we multiply by the constant k.

Varies

*inversely*means we divide k by the term which has inverse variation.