Question

How do you find the radius of a Tetrahedron?

Answer 1

Answer:

The center of the tetrahedron divides each of the four heights (or medians) in the ratio 1:3 (in an equilateral triangle the corresponding ratio is 1:2). The smaller part is also the radius of the inscribed sphere. Therefore the radius of this sphere is one quarter of the height or 9 in your case.