Question

An arc of length 121 cm makes an angle 77° at the centre of a circle. What is the radius of the circle?​

Answer 1

Given ,

Length of arc of a sector = 121 cm

Central angle (Φ)= 77

We know that , the length of arc of a sector of a circle is given by

$\boxed{ \sf{Length \: of \: arc = \frac{ \theta}{360} \times 2\pi r}}$

Thus ,

$\sf \mapsto r = \frac{121 \times 360 \times 7}{77 \times 2 \times 22} \\ \\\sf \mapsto r = 90 \: \: cm$

$\sf \therefore \underline{The \: radius \: of \: circle \: is \: 90 \: cm}$