Find the length of the arc of a circle with radius 5 cm, if its central angle is 70°.
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → \(\frac{35}{18}\pi\) cm
An arc is the same fraction of the circumference as its central angle is of 360°, so \(l=\frac{\theta}{360^{\circ}}\times2\pi r\).
With \(\theta=70^{\circ}\) and \(r=5\) cm: \(\displaystyle l=\frac{70}{360}\times2\pi\times5=\frac{700}{360}\pi=\frac{35}{18}\pi\) cm