1 / 10

Circumference of a Circle

Circumference of a Circle. Math 10-3 Ch.3 Measurement. Properties of Circles…. Yesterday we talked about the perimeter of various 3 sided and 4 sided shapes. How do we find the perimeter of a circle? First, let’s review the properties of the circle:

manning
Télécharger la présentation

Circumference of a Circle

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Circumference of a Circle Math 10-3 Ch.3 Measurement

  2. Properties of Circles… • Yesterday we talked about the perimeter of various 3 sided and 4 sided shapes. How do we find the perimeter of a circle? • First, let’s review the properties of the circle: • *All the points on a circle are equidistant (the same distance) from the CENTER of the circle.

  3. Properties of Circles… • *A line that passes through the center of a circle and touches the edge of the circle on both sides is called the diameter.

  4. Properties of Circles… • *A line that starts at the center of the circle and touches an outside edge is called the radius.

  5. Diameter and Radius… • *The radius can be calculated by dividing the diameter by 2 • *The diameter can be calculated by multiplying the radius by 2

  6. *The circumference of a circle is the perimeter of the circle. It can be calculated with the formula : • Where • C = circumference (perimeter) • = “pi” a constant that is 3.14159…. • d = diameter

  7. Ex1. What is the circumference of a circle with a diameter of 8 cm? • C = ? • d= 8cm • C = x 8 • C = 3.14 x 8 *note: we will use the estimation of 3.14 for pi in this course • = 25.12 cm

  8. Ex2. What is the circumference of a circle with a radius of 2.5 mm? • C = ? • d= ? • r = 2.5 mm • *first we must find the diameter of the circle. • d = 2 x r • d= 2 x 2.5 mm = 5 mm

  9. Ex2. What is the circumference of a circle with a radius of 2.5 mm? • C = x 5 • = 3.14 x 5 • = 15.7 mm

  10. Ex3. The circumference of a circle is 52cm. What is the diameter? • C = 52 cm • d = ? • *We must perform opposite operations (algebra!) to calculate the diameter! • First, fill in the formula with what we know: • 52 cm = 3.14 x d • What is opposite of multiplying by 3.14? Dividing by 3.14 on the other side! • 52 cm 3.14 = d • d = ~16.56 cm

More Related