The length of the altitude of an equilateral triangle is 15 feet. Find the length of one side of the triangle. Find the perimeter.

Answer 1

The length of the base of the right triangle formed by the altitude is 15 tan 30.

That base is half the length of one sides of the triangle, so one side of the triangle is 30 tan 30.

Thus the perimeter (sum of the length of all three sides of the triangle) is 90 tan 30 = 51.96