Nov 2, 2007 -- posted by TechMonk

## Puzzle 6: What’s the radius of the circle?

A simple geometry problem. Shouldn’t take more than a minute to come up with the answer.

After all we all know the radius of the circle is pi*r^2. right ?

The following diagram (not to scale) shows a circle with the center at point C. What is the radius of the circle?

Give proper explanation with your answer.

9.5

ujj is absolutly correct. one of the diagonals of the rectangle is the radius of the circle. since diagonals of a rectangle is equal, the radius of the circle is 8.

7.156

8= sqrt[ (r/2)^2 + (r-3)^2]

solving for r gives 7.156

50.2857142

it shud be 11 i guess…as tan45=(r-3)/8, so r=11.Am I right.

8.

The right angles make the inner figure a rectangle, whose diagonals are of equal length.