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Math Example--Angle Concepts--Angle Measures: Example 42

Math Example--Angle Concepts--Angle Measures: Example 42

Example 42: Negative Reflex Angle (-270 degrees)

Topic

Geometry

Description

This example presents a negative angle of -270 degrees on a polar coordinate graph. The angle is marked in red, and the graph has angles labeled from 0° to -360°. Students are asked to identify the angle shown, with the solution explaining that the absolute value of the angle (270°) makes it a reflex angle, and it is coterminus with 90° (calculated as 360° - 270°).

As part of a series on angle measures, this example helps reinforce the understanding of negative reflex angles and their coterminus positive counterparts. By using a polar coordinate system, students can visualize how these angles relate across different quadrants.

This example aids in developing a comprehensive understanding of angular relationships and classifications.

Teacher Script: "Let's explore this -270-degree angle, class. What does its direction tell us? Can you explain why it's considered a reflex angle? Let's discuss its coterminus angle of 90°. How might these concepts be useful in real-world applications?"

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