This HTML5 app shows a *right triangle*. You can move the vertex of the right angle with pressed mouse button.

a^{2} = c p

b^{2} = c q

b

a^{2} + b^{2} = c p + c q = c (p + q) = c · c = c^{2}

In a right triangle, the sum of the squares on the two legs is equal to the square on the hypotenuse.

a^{2} + b^{2} = c^{2}