Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. If you continue browsing the site, you agree to the use of cookies on this website. See our User Agreement and Privacy Policy.

Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. If you continue browsing the site, you agree to the use of cookies on this website. See our Privacy Policy and User Agreement for details.

Like this presentation? Why not share!

- Circles Lecture - Part 1 by Leo Crisologo 3126 views
- Geometry and the Circles -Jessica B... by buzzajl 282 views
- 9th grade honors geometry by reginanadbielny 2527 views
- Geometry Section 10-1 1112 by Jimbo Lamb 1144 views
- Soh cah toa surveying how things ... by Nathan Lee 374 views
- Lesson 10 5 circles area sector wi... by mlabuski 1251 views

No Downloads

Total views

1,623

On SlideShare

0

From Embeds

0

Number of Embeds

19

Shares

0

Downloads

64

Comments

0

Likes

3

No embeds

No notes for slide

- 1. 6-9 Geometry: Circles and Circumference<br />Today you will learn to calculate the circumference of circles.<br />
- 2. New Vocabulary<br />Circle: set of all points in a plane that are the same distance from a given point called the center.<br />Diameter(d): the distance across a circle through it’s center.<br />Radius (r): the distance from the center to any point on a circle.<br />Circumference (C): the distance around a circle.<br />
- 3. Circles<br />Center<br />.<br />
- 4. Circles<br />Radius<br />
- 5. Circles<br />Diameter<br />
- 6. Circles<br />The diameter of a circle is 2 times the radius.<br />
- 7. Circumference of a Circle<br />The circumference of a circle is equal to it’s diameter (d) times π , or 2 times it’s radius (r) times π. <br />An approximation for π is 3.14.<br />d=2r<br />
- 8. Circles<br />Example: Ferris Wheels<br />Find the circumference of the Ferris wheel that measures 450 ft across.<br />
- 9. Circles<br />Always start by writing the formula that you are going to use.<br /> C=πd<br /> C≈3.14(450)<br /> C≈1,413<br />So, the distance around the Ferris wheel is about 1,413 feet. <br />Replace π with 3.14 and d with 450<br />
- 10. Find the Circumference<br />r=10 in<br />
- 11. Find the Circumference<br />r=10 in<br />C=2πr<br /> C≈2(3.14)(10)<br /> C≈62.8 in<br />
- 12. Find the Circumference<br />22<br />7<br />You can also use<br />for π.<br />Find the circumference of a circle with radius 21 cm.<br />
- 13. Circumference<br />C=2πr<br /> C≈2( )( )<br /> C≈ 132 cm<br />3<br />22<br />7<br />21<br />1<br />1<br />
- 14. Circles<br />Practice (Round to tenths if needed)<br /> 1.diameter = 5 in<br />2. radius = 12 m<br />3. radius = 1 <br />3<br />4<br />
- 15. Homework<br />Practice workbook Lesson 6-9<br />Be sure to show all of your work step by step. This means to write down the formula and show the values you substitute before you multiply. Don’t forget the units in your answer.<br />No work = No credit<br />

No public clipboards found for this slide

×
### Save the most important slides with Clipping

Clipping is a handy way to collect and organize the most important slides from a presentation. You can keep your great finds in clipboards organized around topics.

Be the first to comment