You have previously explored the concept of circumference, otherwise known as the perimeter of a circle. You have also learned about the area of a circle. In this topic, you will explore arc lengths, commonly referred to as a portion of the circumference of a circle. In addition, you will learn how to use ratios to determine the length of an arc and the area of a sector.

Essential Questions

• How do you calculate the area of a sector?
• How do you calculate the length of an arc on a circle?

 

Warm-Up

You already know that there are 360° in a circle. Did you know that there are 180° in a semicircle? Before you learn about arc length and area of a sector, use your knowledge of circles to answer the questions dealing with the angle measures of a circle in this non-graded interactivity. Click the player button to get started.