*Special Congruencies

1) LL Theorem - if the legs of one right triangle are congruent to the corresponding legs of another right triangle, then the triangles are congruent

2) HA Theorem - if the hypotenuse and an acute ngle of one right triangle are congruent to the hypotenuse and an acute angle of another right triangle, then the triangles are congruent

3) LA Theorem - if one leg and an acute angle of one right triangle are congruent to the corresponding leg and acute angle of another right triangle, then the triangles are congruent

4) HL Theorem - if the hypotenuse and a leg of one right triangle are congruent to the hypotenuse and corresponding leg of another right triangle, then the triangle are congruent

*Special Right Triangles

1) 30 - 60 - 90: the hypotenuse is twice as long as the shorter leg, and the longer leg is square root of 3 times as long as the shorter leg

2) 45 - 45 - 90: the hypotenuse is square root of 2 times as long as either leg

*Explorations with GSP