The circumference of a circle exceeds its diameter by 30 cm. Find the radius of the circle. (Use pi = 22/7)
A7 cm
B10.5 cm
C14 cm
D21 cm
Explanation
2*pi*r – 2r = 30 => 2r*(pi – 1) = 30 => 2r*(22/7 – 1) = 30 => 2r*(15/7) = 30 => 30r / 7 = 30 => r = 7 cm.
Exam Relevance
- Topic: Geometry & Mensuration
- Subtopic: Circles
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