Subject: Equilateral triangle in a circle
Name: Michael Setlik
Question: Join each vertex of the triangle to the center of the circle to form three, congruent isosceles triangles. Condider one of these tringles, the one I have shaded green in the diagram. The angle in this triangle at the center of the circle has measure 360^{o}/3 = 120^{o}. The sum of the angles in any triangle is 180^{o} hence each of the other angles in this triangle has measure (180^{o}  120^{o}) = 30^{o}. Thus the isosceles green triangle has two sides of length 3 inches, one angle of 120^{o} and two angles of 30^{o} each. You should now be able to find the length of the third side. Cheers,Harley
