In this lesson students apply the concepts of trigonometry to inscribed and circumscribed polygons. A sorting task about polygon perimeters followed by calculating the perimeter of a regular polygon given only the radius encourages students to notice the structure of right triangles and angles to calculate unknown information (MP7).

This lesson includes an optional activity. Students are given information about elevation changes for different sections of the hike up Mount Everest, and they need to draw their own diagram as well as grapple with converting units.