Geometry and TrigonometryMediumArc length as a fraction of the circumference
Geometry and Trigonometry practice question
A circle has a circumference of 16 units. What is the length of an arc of the circle whose central angle measures 135°?
Answer: 6
The arc is 135/360 = 3/8 of the circumference: (3/8)(16) = 6.
Common wrong answers
- If you answered 3
- 3 is half the arc, using 135/720.
- If you answered 10
- 10 is the rest of the circumference (16 − 6).
- If you answered 2160
- 2,160 is 135 × 16, forgetting to divide by 360.
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