1972 AHSME Problems/Problem 23
Problem 23
The radius of the smallest circle containing the symmetric figure composed of the 3 unit squares shown above is
Solution 1
Draw lines from points and to the center of the circle . As shown from the diagram, is the radius of the circumscribed circle. Set to , so as is , is . Then, and are both right, so an equation can be formed with the Pythagorean Theorem. The radii (hypotenuses) are equal, so the following equation can be made and solved: is solved, so plugging it in to the original formula yields: ~airbus-a321