The Rectangle At The Corner -
Hint
Construct a right-angled triangle in the circle and
use Pythagoras' Theorem.
For any right-angled triangle, Pythagoras' Theorem
states that the squares of the two sides adjacent to the right angle equal
the square of the hypotenuse. If A and B are the lengths of the two sides
and C is the length of the hypotenuse, then
A squared + B squared = C squared. |