This problem wants you to use an equilateral triangle. So an equilateral triangle is a triangle with all the sides the same length, so ** and X the perimeter we just add the three sides up the area. The formula for area is 1/2 base height, so the base here is X. They want you to realize that to find the height, we'd have to drop an altitude. If we drop an altitude that splits that base up into half X on each side, and then by Pythagorean theorem you should be able to find the height. Once you find the height, you literally plug it in. So 1/2 the base was X whatever you find the height to be, based off the Pythagorean theorem of a ^2 + b ^2 = C ^2.