The Student Room Group
Reply 1
2(pi)rh + (pi)r^2 = 250
h= (250 - (pi)r^2) / 2(pi)r

V=(pi)(r^2)(h)
V=[pi(r^2)](250 - (pi)(r^2))/ 2(pi)r

then just factorise it youll get that.

Half way doing this, i figured out that its impossible to track what i did.

Basically you know the formula of the surface area of the open cylinder, so put it equal to 250. Then rearrange equation in terms of h. Then you work out the formula for the volume of a cylinder. Then substitute h into it.
Reply 2
cool, i dun it.....i wasnt adding to get teh surface area, i was multiplying......silly mistakes man