a2 = b2+c2 form needed
Here use differentials
If f = f(x) df = f '(x)dx df is the absolute error df/f is the relative eror
Since the length is known exactly
V = V (r)
V = pi r^2 h = 12pi r^2
dV = 24pi r dr
r= 3 dr is the uncertainty in the measurement dr= .0025
Absolute error = dV = 24 pi (3) (.0025)
For Rel Error note V is given by
Then V = 12* 9 *pi
dV/V = 2(.0025)/3