1. Orchard Hideout Circles – terms and definitions circle:Set of points that are equidistant from a given point, which is know as the center. center

2. Orchard Hideout Circles – terms and definitions radius:(Measure of) line segment whose endpoints are the center and a point on the circle. radius

3. Orchard Hideout Circles – terms and definitions diameter:(Measure of) line segment whose endpoints are on the circle and whose midpoint is at the center of the circle. diameter The diameter is also at the widest part of the circle.

4. Orchard Hideout Circles – terms and definitions circumference:Distance around the circle. circumferenceLatin meaning of circum is "around"

5. Orchard Hideout Circles – terms and definitions When working with circles, we will often have to use… … so where does this mysterious number come from? What does it have to do with circles? Let's find out!

6. Orchard Hideout Circles – equations In each of the following equations: r = measure of radius d = measure of diameter C = measure of circumference

7. Orchard Hideout Circles – calculating values Use the given value to find the other values: 1.If r = 7 units, then… d = _________ C = _________

8. Orchard Hideout Circles – calculating values Use the given value to find the other values: 2.If d = 10.5 units, then… r = _________ C = _________

9. Orchard Hideout Circles – calculating values Use the given value to find the other values: 3.If C = 86π units, then… r = _________ d = _________

10. Orchard Hideout Circles – calculating values Use the given value to find the other values: 4.If C = 30.72 units, then… r _________ d _________

11. Orchard Hideout Circles – calculating values 5.A circular pool has an approximate circumference of 56.5 feet. What are the diameter and radius of the pool? Round to the nearest hundredth.

12. Orchard Hideout Circles – calculating values 6.Find the measure of the radius of a circle whose diameter has endpoints at (7, 2) and (3, 8).