radius – the distance from the center of the circle to the endpoint
TRANSCRIPT
The symbol π (pi)= 3.14. We are going to use π = 3 (Which
is an estimate for π, since there are about 3 diameters in Circumference. )
So whenever you see the symbol π replace it with 3.
What is π?
To find the circumference of a circle, you must use the formulas located on your TAKS Measurement Chart…
If you know the radius, use this circumference formula….. 12 m
C = 2 π r
If you know the diameter, use this circumference formula….. 24 m
C = π d
Use C = 2 ∙ π ∙ r, since the radius is given in this problem.
C = 2 ∙ π ∙ ror
C = π ∙ d
Step 2 Choose the Formula…Write it down!
8 m
Example 2: Try on your own
Diameter = 2 x radius
Diameter = 2 x 8Diameter = 16m
What is the Diameter and Circumference?
C = 2 ∙ π ∙ rC = 2 ∙ 3 ∙ 8
C = 6 ∙ 8C = 48 m
radius
20 ft
Example 3: Try on your own
Radius = Diameter / 2
Radius = 20 / 2Radius = 10 ft
What is the Radius and Circumference?
C = π ∙ dC = 3 ∙ 20C = 60 ft
diameter