Subject: Equilateral triangle in a circle
Name: Michael Setlik
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 360o/3 = 120o. The sum of the angles in any triangle is 180o hence each of the other angles in this triangle has measure (180o - 120o) = 30o. Thus the isosceles green triangle has two sides of length 3 inches, one angle of 120o and two angles of 30o each. You should now be able to find the length of the third side.Cheers,