c. Theorem 3. Two triangles are congruent if the three sides of one triangle are equal,

respectively, to the three sides of the other triangle, as shown in Figure 3-29.

d. Theorem 4. Two right triangles are congruent if the hypotenuse and a leg of one triangle are

equal to the hypotenuse and a leg of the other triangle, as shown in Figure 3-30.

equal to the sum of the squares of the other two sides. This relationship is known as the Pythagorean

theorem.