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Math Example--Angle Concepts--Angle Measures: Example 47

Math Example--Angle Concepts--Angle Measures: Example 47

Example 47: Reflex Angle (345 degrees)

Topic

Geometry

Description

This example features an angle of 345 degrees on a polar coordinate graph. The graph includes degree markings at regular intervals, and the red line extends from the center to the 345° mark. Students are asked to identify the angle shown, with the solution explaining that it is a reflex angle because its measure is greater than 180°, and it is coterminus with 15° (calculated as 360° - 345°).

This example helps students understand how varying degrees affect classification while reinforcing knowledge about angular relationships within different contexts.

Teacher Script: "Let's examine this 345-degree angle, class. What makes it special? Can you explain why it's considered a reflex angle? Lastly, let's discuss its coterminus angle of 15°. How might understanding these concepts be useful in fields like architecture or graphics design?"

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