CircumferenceFormula
Let be the diameterof a circle,and the circumference.Example 1
A circleis inscribedin a square.Eachside of the squareis cm long.Whatis the circumferenceof the
circle?
Use. The length of a side of the square is also the diameter of the circle.Note that sometimesan approximationis givenusing. In this examplethe circumferenceis
cm usingthat approximation.An exactis givenin termsof (leavingthe symbolfor in the answerrather
than multiplyingit out. In this examplethe exactcircumferenceis.
Arc Length
Arcs are measuredin two differentways.
- Degreemeasure:The degreemeasureof an arc is the fractionalpart of a completecirclethat
the arc is.- Linearmeasure:This is the length,in unitssuchas centimetersand feet, if you traveledfrom one end
of the arc to the otherend.
Example 2
Find the lengthof.
=. The radiusof the circleis inches.