The altitude of an equilateral triangle forms a 30-60-90 right triangle where the side of the equilateral triangle is the hypotenuse and the altitude is the long leg. The sides of a 30-60-90 right triangle are in proportion . Hence, if the side of the equilateral triangle measures , then the altitude must measure .
A little algebra music, Sammy:
Now that you have one side of your equilateral triangle, you should be able to compute the perimeter yourself.
John
My calculator said it, I believe it, that settles it
