a paint can holds 2.5 litres of paint and has a height of 19cm work out the radius?

pi r^2 h = volume

pi r^2 (19)= 2500 (2500 cc^3 is 2.5 liters) solve for r

i dont seem to understand how would i work this out this is for homework and ive been stuck on it for 3 hrs now...

2500 = pi * r^2 * 19 divide both sides by 19 pi

r^2 = 2500 / ( 19 pi)

Take the square root

r = sqrt [ 2500 / (19 pi) ] ≈ 6.47 cm