Question

A metallic right circular cone 20cm high and whose vertical angle is 90° is cut into two parts at the middle point of its axis by a plane parallel to base. If frustum so obtained bee drawn into a wire of diameter (1/16)cm. find length of the wire?

Answer 1

Let ABC be cone. Height of metallic cone AO = 20cm

Cone is cut into two parts at the middle point of its axis

Hence height of frustum cone AD = 10cm

Since angle A is right angled. So each angles B and C = 45°

Angles E and F 45°

Let radii of top and bottom circles of frustum cone bee r₁ and r₂ cm