A sphere is inscribed in a right circular cone whose slant high and diameter are both 20 inches. Find the surface area of the inscribed sphere.

Question

directrix · Answer

Diagram

directrix · Answer

A sphere is inscribed in a right circular cone whose slant high and diameter are both 20 inches --- I assume the question means that the diameter of the right circular cone is 20.

directrix · Answer

Similar 30 60 90 Triangles

directrix · Answer

I am stuck on this at the moment. I need to think. Maybe you or others will post ideas.

wolframwizard · Answer

I got it using similar triangles. You have to draw a triangle using the line from the center of the sphere to the point where the sphere touches the cone and the line from the vertex of the cone to the center.