1. Warm Up Decode these words and phrases. Mind 2. LU CKY Matter
3. water stand
swimming do you
Mind over matter
Lucky break
Swimming under water
Do you understand

2. MR DUCKS MR NOT DUCKS MR 2 DUCKS CM WANGS LIB MR DUCKS
Warm Up Continued…
MR DUCKS MR NOT DUCKS MR 2 DUCKS CM WANGS LIB MR DUCKS

3. Lesson 4.1: Circumference of a Circle
I can:
Identify the radius and diameter of a circle.
State the formula for circumference of a circle.
Find the radius and diameter of a circle, given the circumference.
Vocabulary:
Radius
Diameter
Circumference Pi

4. Center of a Circle
The point in a circle which all points on the circle are equidistant from.

5. Radius
The distance from the center of a circle to a point on the circle.

6. Diameter
The distance across a circle through its center point.

7. Circumference *the red indicates Circumference
The distance around the edge of a circle. (Perimeter of a circle)
*the red indicates Circumference

8. Pi
The circumference of any circle, divided by its diameter. We will denote pi by the number * If you take any circle and find the circumference and diameter, no matter what the size circle, you will always get Pi .

9. Formulas
If we know the radius and we are trying to find the circumference, we use
If we know the diameter and we are trying to find the circumference, we use

10. Example 1:
1. We know our formula to find the circumference, given the radius, is 2. Now, all we have to do is plug in the values given to us into our equation and solve. 4

11. Example 2:
1. We know our formula to find the circumference, given the diameter,is 2. Now, all we have to do is plug in the values given to us into our equation and solve. 10

12. Try these examples:
2.5 6 22 25

13. Answers: 6
2.5
7.85
37.68 22 25
69.08
157