Question

on increasing each radius of the base and height of a cone by 20 percent. By what percentage the volume be increased?

Answer 1

radius of new cone= 12/10r
/height=12/10h
volume=1728/3000$\pi$$r^{2}$h
volume of old cone=1/3$\pi$$r^{2}$h
percentage change= 72.8%

Answer 2

Base radius of cone = R
height = H
Volume = π/3 * R² H

New radius:    120/100 * R = 1.2 R
New height :   120/100 * H = 1.2 H
New Volume = π/3 * 1.2² R² * 1.2 H = 1.728 V

Increase in volume = (1.728 - 1) V / V *100
                    = 72.8 %