Step-by-step explanation:

Let original radius of cone=R

And original height=H

Hence original volume V=(1/3)πR²H

New radius when reduced by10%=R-(10/100)R =0.9R

New height when increased by 11 1/9 % i.e. 100/9% =H+(100/9)R/100=10/9H

Hence new volume V₁=(1/3)(0.9R)²(10/9H) =(1/3)(0.81R²)(10/9H=(1/3)(0.90)R²H=0.90V

Reduction in volume =V-0.90V=0.10V

Percentage reduction =(0.10V/V)×100= 10 %