Word problem involving an increase in volume but not height?

The problem is 'The volume of a cylinder of height h and radius r is given by V=pir^2h; a particular cylindrical tank is 15 m tall and has a radius of 8 m. i want to construct another cylindrical tank with a volume 20 percent greater but having the same height. How large must its radius be?"

I don't even know where to start. I am very new to matlab. Any help anyone can give would be really appreciated.

[Steven Lord]

How would you solve this with pencil and paper? Once you know that you may be able to translate some of those steps into MATLAB code.

[Leesy]

If i where to solve this on paper, I would probably set up parallel equations and find what remains constant for both (in this case the height) and solve it that way. I do not know how to do this in Matlab.

[Walter Roberson]

You work it out on paper and then implement the resulting formula in MATLAB.