Demonstrates how to solve a challenging geometry problem about finding the measure of an angle that is formed by different segments in a square which intersect with part of a circle. Solution depends on creating triangles in the diagram...

Explains how to solve for multiple missing angles in a diagram composed of multiple triangles using the triangle sum theorem and other angle relationships. This video also appears in the Geometry: Triangles strand. [5:42]

Demonstrates how to solve five different problems from a released California Geometry state test that involve finding the measures of angles in different polygons. This video also appears in the Geometry: Worked Examples section. [10:58]

Explains how to use given triangle congruency statements to determine the unknown measures of all angles in a diagram where one large triangle is divided into three congruent triangles. [4:35]

Demonstrates how to use the triangle sum theorem, properties of equilateral and isosceles triangles, and special angle pairs to determine the unknown measures of angles in three different diagrams. [6:27]

Demonstrates how to use the triangle sum theorem, properties of isosceles triangles, and special angle pairs formed when parallel lines are cut by a transversal to set up an equation using given algebraic expressions for angle measures...

Explains how to use given algebraic expressions for the measures of angles in an isosceles triangle and apply knowledge of the triangle sum theorem and the knowledge that the base angles of an isosceles triangle are congruent to...

Shows how to find the measure of missing angles using the triangle sum theorem and vertical angles. This video also appears in the Geometry: Triangles strand. [4:55]

Explains how to use the triangle sum theorem to solve for missing angle measures in a triangle. Also addresses the relationship between the measure of an exterior angle of a triangle and the measures of the remote interior angles. This...