An equilateral triangle with one side 6cm is inscribed in a circle with its three vertices on the circumference. What is the diameter of the circle?

(In reply to solution by joy)

Remember that when you draw the altitude, the outside edge of the triangle is no longer 6 cm, but 3 cm.
This edge is opposite the 60° angle, so the length of the hypotenuse is 3 cm/sin 60°, which is equal to 2√3.

You were off by a factor of two I think because you forgot that the 6 cm is not an edge of the 3-60-90 triangle you were considering.

Posted by DJ on 2003-06-17 17:45:04