The height of the candle is 13cm and the circumference of the candle is 31.416cm. to the nearest centimeter how much wax is needed to make another candle

This is the concept of volumes of solid materials, to get the amount of wax needed to make the candle we will require to calculate for the volume of the candle.
volume=πr^2h
since we are given the circumference of the candle we need to get the radius first;
C=πd
C=31.416 cm
31.416=πd
d=31.416/π
d=10.0000 cm
Therefore the radius will be 5 cm. 
The volume of the wax required to make the candle will be:
V=πr^2h
V=π*5^2*13
V=1,021.02 cm^3