A cone, with a base of 10 cm diameter and axis of 12 cm, is lying on Horizontal Plane (HP) along its generator

A cone, with a base of 10 cm diameter and axis of 12 cm, is lying on Horizontal Plane (HP) along its generator. The internal angle which the base of the cone makes with the HP is__________degrees.

1. 67°
2. 7.6°
3. 67.6°
4. 37.6

Ans: 67.6°

Explanation:

tan θ =height/base=12/5

θ=67.6°

Alternatively, using Pythogorean theorem, hypotenuse i.e. the length of the cone is calculated to be 13 cm.