Question

CDEF is a square of side length 20 cm. CD is a chord and EF is a tangent to the circle.

What is the radius of the circle?

Answer 1

This is a fabulous question I found on a blog. Curious as to how many good thinkers there are on here.

Answer 2

Cute!

Answer 3

@dumbcow
Why did you delete your answer?

Answer 4

it was wrong, i found a mistake :(

Answer 5

yeah, answer should be radius is 12.5

Answer 6

\[r^2 = 10^2 + (20-r)^2\]
\[r = \frac{25}{2} = 12.5\]