Geometry and TrigonometryVery hardRadius from a sector's area and angle
Geometry and Trigonometry practice question
A sector of a circle has a central angle of 120° and an area of 12π. What is the radius of the circle?
Answer: 6
(120/360)πr² = 12π gives r² = 36, so r = 6.
Common wrong answers
- If you answered 4
- 4 uses r² = 16 from 12π ÷ (3/4).
- If you answered 12
- 12 copies the area's coefficient.
- If you answered 36
- 36 is r².
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