Math Example--Polygons--Triangle Classification: Example 20
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Geometry >> Triangles >> Definition of a Triangle

Math Example--Polygons--Triangle Classification: Example 20

Math Example--Polygons--Triangle Classification: Example 20

A triangle with two congruent angles of 45° and an unknown angle x.

Topic

Triangles

Description

This example shows a triangle with two known angles of 45° and an unknown angle x. Solving for x, we find it to be 90°, classifying this as a right triangle with two congruent angles, making it an isosceles right triangle.

Triangle classification may be based on side lengths or angles. Right triangles have a 90° angle, while isosceles triangles have two equal sides or angles. Examples like this help students understand combined classifications.

Seeing multiple examples reinforces students’ ability to identify and classify triangles consistently by using angle or side properties.

Teacher's Script: "Here, solving for the unknown angle gives a 90° angle, making this a right triangle. The two congruent angles also make it isosceles. Recognizing these features helps us apply the correct classification."

For a complete collection of math examples related to Triangles, click on this link: Math Examples: Triangle Classification Collection.

Common Core Standards CCSS.MATH.CONTENT.7.G.A.2, CCSS.MATH.CONTENT.4.G.A.2, CCSS.MATH.CONTENT.5.G.B.3
Grade Range 4 - 7
Curriculum Nodes Geometry
    • Triangles
        • Definition of a Triangle
Copyright Year 2013
Keywords triangles, classification