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Question
The radius of the circle whose arc of length 15 π cm makes an angle of \[\frac{3\pi}{4}\] radian at the centre is
Options
10 cm
20 cm
- \[11\frac{1}{4}cm\]
- \[22\frac{1}{2}cm\]
Solution
20 cm
\[\theta = \frac{\text{ Arc }}{\text{ Radius}}\]
\[ \Rightarrow \frac{3\pi}{4} = \frac{15\pi}{\text{Radius}}\]
\[ \Rightarrow \text{ Radius }= \frac{60}{3} = 20 cm\]
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