Referring to the attached pic, find the radii of both circles.
Then, if the radius of the smaller circle isand if , then (tangents from a point to a circle are equal)
In cm (Pythagoras)
Solving these simultaneous equations: .
So the radius of the smaller circle is cm.
Similarly let and
Express the lengths of and in terms of and . Then use the fact that to form another equation. Solve these equations to find , the radius of the larger circle.