If you have an equilateral triangle, the median is also the altitude so - That means that if you draw altitude, it will bisect the base of the triangle and meet at two right angles. That gives you two of the measurements for the right triangle - the side (6) hypotenuse, and the base (3). You can then figure out the height using the Pythagorean as you have the a and the c for the theorem. Then you can use 1/2 base times height to find the area.
