What is the altitude of an equilateral triangle with side of 4.0m?

ok I know all sides and angles are equal. so i drew a triangle with all sides of 4.0 and all angles of 90. then I divided it vertically to get the altitude. which would give me a side of 4.0m, a side of 2.0m, a 90 angle and a 45 angle. I do not know how to set this up to solve. i am looking for the hypotenuse but just can't seem to find the right way to set up

thanks!