CK-12 Geometry-Concepts

http://www.ck12.org Chapter 4. Triangles and Congruence

4.1 Triangle Sum Theorem

Here you’ll learn that the sum of the angles in any triangle is the same, due to the Triangle Sum Theorem.

What if you wanted to classify the Bermuda Triangle by its sides and angles? 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 from a map are in the image. What type of triangle is this? 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? After
completing this Concept, you’ll be able to determine how the three angles in any triangle are related in order to help
you answer these questions.

Watch This

MEDIA

Click image to the left for use the URL below.

URL: http://www.ck12.org/flx/render/embeddedobject/52608

CK-12 Foundation: Chapter4TriangleSumTheoremA

MEDIA

Click image to the left for use the URL below.

URL: http://www.ck12.org/flx/render/embeddedobject/1320

James Sousa: Proving the Triangle Sum Theorem