Question

Find the volume of a right circular cone with: 

height 21 cm and slant height 28 cm. 

Answer 1

From the relation 

`l^2=r^2+h^2,`we have  

`r=sqrt(l^2-h^2)=sqrt((28)^2)-(21)^2=7sqrt7cm`  

So, volume of cone =`1/3xxpir^2xxh` 

`=1/3xx22/7xx(21)^2xx(7sqrt7)^2` 

`=7546cm^3`