If radius of cone decreases by 50% and its height increases by 20%. Then find the percentage change in the volume.
Let initial radius and height of cone be r and h respectively.
Then the final raidus and height will become r−0.5r and h+0.2h.
Let the change in volume be X
Change in volume× Volume of Cone without change=Volume of Cone after change
X×13×π×r2×h=13×π×(0.5r)2×1.2h
X=0.3
Which means 70% decrease