you do not give a value for PI so I am using 3.14
V=PI x r^2 x H
you know volume and radius so put those into the equation
525 = PI (3.14) x 5^2 x H
525 = 3.14 x 25 x H
525 = 78.5 x H
divide both sides by 78.5
6.687 = H
round off answer as needed 6.7cm or 6.69cm
NOTE : the answer may vary slightly depending on the value of PI used.
but this is how you calculate the height.