1. Triangle Theorems

2. Warm-Ups 1.What do you think is going well with this class? 2.What is your favorite part of the class? 3.What do you wish was different about this class? Be Honest and Be Specific!

3. The Triangle Sum Theorem The sum of the interior angles of any triangle is equal to 180 degrees.

4. Examples Find the value of the missing angle:

5. Midsegment in Triangles The mid-segment of a triangle (also called a midline) is a segment joining the midpoints of two sides of a triangle.

6. Mid-segment Theorem Properties 1)The mid-segment of a triangle joins the midpoints of two sides of a triangle such that it is parallel to the third side of the triangle 1) The mid-segment of a triangle joins the midpoints of two sides of a triangle such that its length is half the length of the third side of the triangle.

7. Example Solve for x:

8. Isosceles Triangle Theorem If two sides of a triangle are congruent, the angles opposite them are congruent.

9. Examples