1. Circles – Circumference and Area Circumference – the distance around a circle

2. Circles – Circumference and Area Circumference – the distance around a circle It turns out, if you divide any circle by its diameter you get pi. Pi is a non- repeating, non-terminating decimal. We’ll always use 3.14 as an approximate value when calculating using Pi.

3. Circles – Circumference and Area Circumference – the distance around a circle It turns out, if you divide any circle by its diameter you get pi. Pi is a non- repeating, non-terminating decimal. We’ll always use 3.14 as an approximate value when calculating using Pi. Example # 1 : The radius of a circle = 4 inches. Find diameter = ? circumference = ?

4. Circles – Circumference and Area Circumference – the distance around a circle It turns out, if you divide any circle by its diameter you get pi. Pi is a non- repeating, non-terminating decimal. We’ll always use 3.14 as an approximate value when calculating using Pi. Example # 1 : The radius of a circle = 4 inches. Find diameter = 8 inches circumference = ?

5. Circles – Circumference and Area Circumference – the distance around a circle It turns out, if you divide any circle by its diameter you get pi. Pi is a non- repeating, non-terminating decimal. We’ll always use 3.14 as an approximate value when calculating using Pi. Example # 1 : The radius of a circle = 4 inches. Find diameter = 8 inches circumference = 25.12 inches

6. Circles – Circumference and Area Circumference – the distance around a circle It turns out, if you divide any circle by its diameter you get pi. Pi is a non- repeating, non-terminating decimal. We’ll always use 3.14 as an approximate value when calculating using Pi. Example # 2 : The circumference of a circle = 47.1 feet. Find diameter = ? radius = ?

7. Circles – Circumference and Area Circumference – the distance around a circle It turns out, if you divide any circle by its diameter you get pi. Pi is a non- repeating, non-terminating decimal. We’ll always use 3.14 as an approximate value when calculating using Pi. Example # 2 : The circumference of a circle = 47.1 feet. Find diameter = 15 feet radius = ?

8. Circles – Circumference and Area Circumference – the distance around a circle It turns out, if you divide any circle by its diameter you get pi. Pi is a non- repeating, non-terminating decimal. We’ll always use 3.14 as an approximate value when calculating using Pi. Example # 2 : The circumference of a circle = 47.1 feet. Find diameter = 15 feet radius = 7.5 feet

9. Circles – Circumference and Area Area of a Circle – the amount of square units inside the circle

10. Circles – Circumference and Area Area of a Circle – the amount of square units inside the circle Example 1:The radius of a circle is 3 inches. What is the area? Solution: = 3.14 · (3 in) · (3 in) = 3.14 · (9 in 2 ) = 28.26 in 2

11. Circles – Circumference and Area Area of a Circle – the amount of square units inside the circle Example 2 : The area of a circle is 78.5 square meters. What is its radius ? Solution :

12. Circles – Circumference and Area Knowing the circumference of a circle can help us find lengths of arcs in circles and central angle measurements. The total number of degrees in a circle = 360 degrees. We can use proportions to solve these problems.

13. Circles – Circumference and Area Knowing the circumference of a circle can help us find lengths of arcs in circles and central angle measurements. The total number of degrees in a circle = 360 degrees. We can use proportions to solve these problems. Example : Find arc AC if radius = 4 cm and measure of angle AOC = 30 degrees. C A O 2 30°

14. Circles – Circumference and Area Knowing the circumference of a circle can help us find lengths of arcs in circles and central angle measurements. The total number of degrees in a circle = 360 degrees. We can use proportions to solve these problems. Example : Find arc AC if radius = 4 cm and measure of angle AOC = 30 degrees. C A O 2 30° Solution :

15. Circles – Circumference and Area Knowing the circumference of a circle can help us find lengths of arcs in circles and central angle measurements. The total number of degrees in a circle = 360 degrees. We can use proportions to solve these problems. Example : Find arc AC if radius = 4 cm and measure of angle AOC = 30 degrees. C A O 4 30° Solution :

16. Circles – Circumference and Area Knowing the circumference of a circle can help us find lengths of arcs in circles and central angle measurements. The total number of degrees in a circle = 360 degrees. We can use proportions to solve these problems. Example : Find circumference if arc AC = 24 inches and measure of angle AOC = 60 degrees.. C A O 24 60°

17. Circles – Circumference and Area Knowing the circumference of a circle can help us find lengths of arcs in circles and central angle measurements. The total number of degrees in a circle = 360 degrees. We can use proportions to solve these problems. Example : Find circumference if arc AC = 24 inches and measure of angle AOC = 60 degrees.. C A O 24 60° Solution :