We shall now learn how to construct a right triangle if we are given the lengths of the two legs. Have your ruler and compasses out and follow along with the applet, constructing your own triangle. Use for example lengths 4 inches for BC, 3 inches for AC. AB will be the hypotenuse.
If on the other hand we know the length of one leg and the hypotenuse we can still construct the triangle. The applet below shows you how: