http://www.ck12.org Chapter 4. Triangles and Congruence
4.1 Triangle Sums
Learning Objectives
- Understand and apply the Triangle Sum Theorem.
- Identify interior and exterior angles in a triangle.
- Understand the Exterior Angle Theorem.
Review Queue
Classify the triangles below by their angles and sides.
1.
2.
3.
- How many degrees are in a straight angle? Draw and label a straight angle,^6 ABC.
Know What?Below is a map of the Bermuda Triangle. You are probably familiar with the myth of this triangle;
how several ships and planes passed through and mysteriously disappeared.
The measurements of the sides of the triangle are in the image. What type of triangle is this? Classify it by its sides
and angles. Using a protractor, find the measure of each angle in the Bermuda Triangle. What do they add up to?
Do you think the three angles in this image are the same as the three angles in theactualBermuda triangle? Why or
why not?