Source: Animation 7, MG, Wikimedia Commons

Circles and the geometry of circles are important for describing many real-world relationships. Because the Earth is roughly a sphere, aeronautical engineers must use circles to calculate distances and angle relationships. Landscapers and architects also use circles in their designs, so they need to know how to calculate segment and angle relationships.

In this lesson, you will investigate relationships among segments created by circles and lines that intersect circles.

Before continuing in the lesson, let’s review some important vocabulary that you will use when working with circles.

Given the following image, click on the appropriate segment on or in the circle for each name displayed above it. Copy your completed image into your notes.