Question

The curved surface area of a cone is 12320 cm². If the radius of its base is 56 cm, find its height.

Answer 1

Curved surface area = 12320 cm²

Radius of base (r) = 56 cm

Let slant height = l 

∴ πrl = 12320

`=> 22/7 xx 56 xx l = 12320` 

`=> l = (12320 xx 7)/(56 xx 22)` 

`=>` l = 70 cm  

Height of the cone

= `sqrt(l^2 - r^2)` 

= `sqrt((70)^2 - (56)^2 ` 

= `sqrt(4900 - 3136)`  

= `sqrt(1764)` 

= 42 cm