You can put this solution on YOUR website! If you draw the relection of the triangle on the long leg, you will have two congruent triangles that form a triangle with three 60 degree angles. The black triangle plus its red reflection form an equilateral triangle.
The hypotenuse of the original right triangle is one side of the equilateral triangle.
The short leg of the original right triangle is half of one side of the equilateral triangle, so it is half of the hypotenuse;
short leg = (1/2) * hypotenuse
