Problem:
Square  has side length . A semicircle with diameter  is constructed inside the square, and the tangent to the semicircle from  intersects side  at . What is the length of 

Answer Choices:
A.  
B.  
C.  
D.  
E.  
Solution:
Let be the point at which is tangent to the semicircle, and let be the midpoint of . Because and are both tangents to the semicircle, . Similarly, . Let . The Pythagorean Theorem applied to gives
It follows that and .

Answer: .
The problems on this page are the property of the MAA's American Mathematics Competitions