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Math Example--Solving Equations--Equations Using the Exterior Angle Theorem--Example 9

Equations Using the Exterior Angle Theorem--Example 9

Exterior Angle Theorem Example 9

Topic

Equations

Description

This example presents a more challenging application of the Exterior Angle Theorem in solving triangle-related equations. In this scenario, we have a triangle with one known interior angle of 25°, an unknown interior angle y, and an unknown exterior angle x. The Exterior Angle Theorem states that an exterior angle of a triangle is equal to the sum of the two non-adjacent interior angles. Here, the equation is set up as x = 25° + y. 

You can also use the fact that x and 2x are supplementary, allowing you to solve for x. By solving for x, you can then solve for y using the triangle equation.

This problem demonstrates how the theorem can be used to establish a relationship between unknown angles in a triangle. Unlike previous examples, this one doesn't provide a direct solution but rather sets up an equation that relates the unknown angles. To fully solve this problem, additional information or constraints would be needed. The methodology for approaching such equations involves identifying the known and unknown angles, setting up the equation based on the theorem, and recognizing that further information is required for a complete solution. This type of problem encourages students to think critically about the relationships between angles in a triangle and understand that sometimes in mathematics, we can establish relationships without having enough information for a unique solution. It serves as an excellent introduction to more complex geometric problems and systems of equations, preparing students for advanced topics in mathematics and geometry.

For a complete collection of math examples related to Equations That Use the Exterior Angle Theorem click on this link: Math Examples: Equations That Use the Exterior Angle Theorem Collection.

Common Core Standards CCSS.MATH.CONTENT.8.G.A.5
Grade Range 6 - 8
Curriculum Nodes Geometry
    • Triangles
        • Applications of Triangles
Copyright Year 2021
Keywords exterior angles, exterior angle theorem, supplementary angles