Isosceles Triangles. Sec: 4.6 Sol: G.5. 3. Leg. Leg. 1. 2. Base. Properties of Isosceles Triangles. An isosceles triangle is a triangle with two congruent sides. The congruent sides are called legs and the third side is called the base. Vertex. Base Angles. A. B. C.
BaseProperties of Isosceles Triangles
An isosceles triangle is a triangle with two congruent sides.
The congruent sides are called legs and the third side is called the base.
CTheorem 4.9 Isosceles Triangle Theorem
If two sides of a triangle are congruent, then the angles opposite those sides (base angles) are congruent.
What is the measure of
3x - 7
If two angles of a triangle are congruent, then the sides opposite those angles are congruent.
Find the value of x.
Since two angles are congruent, the
sides opposite these angles must be
3x – 7 = x + 15
2x = 22
X = 11
Lesson 3-2: Isosceles Triangle
4.3 A triangle is equilateral if and only if it is equiangular.
4.4 Each angle of an equilateral triangle measures 60°.
Find the measure of angle 1 and 2:
Solve for X:
Classwork: WB pg 51 1-6
Homework: Worksheet 4-6