Math Example--Angle Concepts--Angle Measures: Example 41

Topic

Geometry

Description

This example features a negative angle of -255 degrees on a polar coordinate grid. The angle is marked with a red line starting from the origin and extending to its position. Students are asked to identify the angle shown, with the solution explaining that the absolute value of the angle (255°) makes it a reflex angle, and it is coterminus with 105° (calculated as 360° - 255°).

As part of a comprehensive series on angle measures, this example further explores concepts related to negative reflex angles and their coterminus positive counterparts. By using a polar coordinate system, students can visualize how these types of angles relate across different quadrants.

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 -255-degree angle, class. What does this tell us about its direction? Can you explain why it's considered a reflex angle? Lastly, let's discuss its coterminus angle of 105°. How might understanding these concepts be useful in fields like navigation or physics?"

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