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Math Example--Angle Concepts--Angle Measures: Example 15

Math Example--Angle Concepts--Angle Measures: Example 15

Example 15: Reflex Angle (225 degrees)

Topic

Geometry

Description

This example showcases a reflex angle of 225 degrees on a polar coordinate grid. The angle is marked in red and measured clockwise from the 0° line. Students are asked to identify the angle, with the solution explaining that it is a reflex angle because its measure is greater than 180 degrees.

As part of a series on angle measures, this example helps students understand the range of reflex angles. The use of a polar coordinate system allows students to visualize how angles relate to the coordinate axes and reinforces their understanding of angle classification.

Presenting multiple examples of reflex angles with different measures helps students develop a nuanced understanding of the concept. This repetition is crucial for building confidence in angle identification and classification.

Teacher Script: "Let's examine this 225-degree angle, class. How does it compare to the previous reflex angles we've seen? Notice how it's exactly halfway between 180 degrees and a full rotation. Why is this significant? Can anyone think of a real-world example where we might encounter a 225-degree angle?"

For a complete collection of math examples related to Angle Measures click on this link: Math Examples: Angle Measures Collection.

Common Core Standards CCSS.MATH.CONTENT.4.G.A.1, CCSS.MATH.CONTENT.7.G.A.2, CCSS.MATH.CONTENT.4.MD.C.5.B, CCSS.MATH.CONTENT.4.MD.C.6, CCSS.MATH.CONTENT.4.MD.C.7
Grade Range 4 - 8
Curriculum Nodes Geometry
    • Angles and Planes
        • Definition of an Angle
Copyright Year 2013
Keywords angle measure