Question

The perpendicular height of a cone is 12 cm and its slant height is 13 cm. Find the radius of the base of the cone. 

Answer 1

Let the radius of the base of the cone be r cm.

Height of the cone, h = 12 cm

The slant height of the cone, l = 13 cm

Now,

`"r"^2 +"h"^2 = "l"^2`

⇒ `"r"^2 + (12)^2 = (13)^2`

⇒ `"r"^2 + 144 = 169`

⇒ `"r"^2 = 169 - 144 = 25`

⇒ `"r" = sqrt(25) = 5  "cm"`

Thus, the radius of the base of the cone is 5 cm.