Referring to the attached pic, find the radii of both circles.

Printable View

- Nov 8th 2009, 07:38 PMukorovquestion on properties of circle 9
Referring to the attached pic, find the radii of both circles.

- Nov 9th 2009, 05:40 AMGrandad
Hello ukorovIn the attached diagram, I have marked the points of contact with the smaller circle as E and F.

Then, if the radius of the smaller circle is

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.

Grandad - Nov 9th 2009, 09:48 AMukorov