geametry word problem

Question

A cylindrical  candle  is to be made from 18 in3 of wax. If the candles height  is twice  its diameter  what radius  and height  should it have, to the nearest  tenth

Answer 1

Use the volume of a cylinder.

 

V = πr²h

 

where:

V = 18

h = 2(2r) = 4r

 

Plug in the values into the equation and solve for r.

 

18 = πr²(4r)

18 = 4πr³

 

 

Divide both sides of the equation by 4π.

 

9 / (2π) = r³

 

 

Then cube-root both sides of the equation to get the radius.

 

Finally, multiply the radius by 4 to get the height.