The document discusses theorems related to triangles, including the base angles theorem, converse of the base angles theorem, properties of equilateral and equiangular triangles, and congruence of right triangles with congruent hypotenuses and legs. It also includes an example problem asking whether two lines are parallel based on given angle measures.

1. Section 4.6

2.  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

3.  Equilateral triangles are also
equiangular
 Equiangular triangles are also
equilateral

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

5. • Find x
81
9x + 18

6. A C
x
82°
y
x
D
B
Are AB and CD parallel?