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Mathematics LibreTexts

2.B: Other Triangle Properties

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Overview

The purpose of this lesson is to identify and use other triangle properties.

This lesson will address the following CCRS Standard(s) for Geometry:

  • 8.G.5: Use informal arguments to establish facts about the angle sum and exterior angles of triangles, above the angles created when parallel lines are cut by a transversal, and the angle-angle criterion for similarity of triangles. For example, arrange three copies of the same triangle so that the sum of the three angles appears to form a line, and give an argument in terms of transversals why this is so

Directions

  1. Take notes while watching videos below
  2. Go to http://wamap.org and log into our course to complete assignment 2.B with 80% or better.

Do

Complete assignment 2.B with 80% or better at http://wamap.org

Summary

In this lesson we have learned:

  • Isosceles triangles have two congruent sides and two congruent angles
  • The sum of the angles of a triangle is 1800
  • The exterior angle of a triangle is equal to the sum of the opposite two angles
  • When combined, the two shortest sides of a triangle are longer than the third (longest) side

2.B: Other Triangle Properties is shared under a not declared license and was authored, remixed, and/or curated by LibreTexts.

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