# An Arc of Length 20𝜋 Cm Subtends an Angle of 144° at Centre of Circle. Find the Radius of the Circle. - Mathematics

An arc of length 20𝜋 cm subtends an angle of 144° at centre of circle. Find the radius of the circle.

#### Solution

Length of arc = 20𝜋cm

O = angle subtended at centre = 144°

Length of arc =theta/360^@× 2𝜋𝑟

=144/360× 2pir =(4pi)/5r

=(4pi)/5r = 20pi

r =(20pi×5)/(4pi)= 25 cms

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#### APPEARS IN

RD Sharma Class 10 Maths
Chapter 13 Areas Related to Circles
Exercise 13.2 | Q 3 | Page 24