1. DRILL Write the converse of the statement:
If today is Monday, then tomorrow is Tuesday.
What is the hypothesis and what is the conclusion?
If he studies, then he will pass the test.

2. Geometry
Objective
Today, we will use and apply properties of isosceles triangles.

3. Vocabulary What You'll Learn
Isosceles Triangles
What You'll Learn
You will learn to identify and use properties of _______
triangles.
isosceles
1) _____________
2) ____
3) ____
Vocabulary
isosceles triangle
base
legs

4. The congruent sides are called ____. legs
Isosceles Triangles
Recall from §5-1 that an isosceles triangle has at least two congruent sides.
The congruent sides are called ____.
legs
The side opposite the vertex angle is called the ____.
base
In an isosceles triangle, there are two base angles, the vertices where the
base intersects the congruent sides.
vertex angle
leg
base angle
base

5. triangle are congruent, then the angles opposite those sides
Isosceles Triangles
Theorem
6-2
Isosceles
Triangle
6-3 A B C
If two sides of a
triangle are congruent,
then the angles
opposite those sides
are congruent.
The median from the vertex angle of an
isosceles triangle lies
on the perpendicular
bisector of the base
and the angle bisector
of the vertex angle. A B C

6. triangle are congruent, then the sides opposite those angles
Isosceles Triangles
Theorem
6-4
Converse of
Isosceles
Triangle A B C
If two angles of a
triangle are congruent,
then the sides opposite those angles
are congruent.
Theorem
6-5
A triangle is equilateral if and only if it is equiangular.

7. Homework
Pages 191 – 192
#’s 1 – 5
#’s 9, 10, 12 – 15
#’s