A regular tetrahedron holds a sphere snugly within its four sides. A larger sphere surrounds the tetrahedron, just touching its four vertices. What is the ratio of radii of the two spheres?

Rad inner = (1/2)tan30 ==> sin30/2cos30
Rad outter = (1/2cos30) ==> 1/2cos30

Dropping denoms, it's "sin30:1" or like Hank said "1:2"

Posted by jude on 2003-04-17 09:41:56