Section 4.6

Base Angles Theorem:◦ If two sides of a triangle are congruent, then their

opposite angles are also congruent.

Converse of the Base Angles Theorem:◦ If two angles of a triangle are congruent, then

their opposite sides are also congruent

Equilateral triangles are also equiangular

Equiangular triangles are also equilateral

If the hypotenuse and one leg of a right triangle are congruent to those of another right triangle, then the two triangles are congruent

• Find x

81

9x + 18

D

A

B

C

Are AB and CD parallel?

x

x82°

y