GM-U4.2 Lesson: Isosceles Triangles

Unit 4 Lesson 2:
Properties of Isosceles Triangles

​Objective:

Students are going to examine properties of isosceles triangles, and use those properties to solve problems.

Isosceles triangle - triangle with two equal sides and angles.

​

Concept:

Solve for x.​

​Example 1:

Solve for x.​

​Example 2:

Solve for x.​

​Example 3:

The End

The next 3 slides have the answers to the examples if you missed or need them.

Solve for x.​

90 - 38 = 52

x = 52

​Example 1:

Solve for x.​

9 = x - 2
+2 +2
11 = x or x = 11

​Example 2:

Solve for x.​

180 - 112 = 68 (supplementary)

180 - 2(68) = 44 (interior angles)

90 - 44 = 46 (right angle)

2x + 20 = 46 (vertical angles)
- 20 -20
2x = 26
2 2

x = 13

​Example 3:

Solve for x.​

180 - 112 = 68 (supplementary)

180 - 2(68) = 44 (interior angles)

90 - 44 = 46 (right angle)

2x + 20 = 46 (vertical angles)
- 20 -20
2x = 26
2 2
x = 13

​Example 3: