Question

an arc of a circle whose radius is 2 centimetre, subtends and angle of 18 degree at centre of the circle. the arc is

Answer 1

SEE WE KNOW THE LENGTH OF THE ARC IS S=r*thita
so in this question radius(r)=2cm and angle (thita)=18*pi/180 radian
so length of the arc will be 0.02*pi/10

Answer 2

$arc \: = \frac{18}{360} \times 2\pi \: r \\ = \frac{1}{20} \times 2 \times 3.14 \times 2 \\ = \frac{1}{20} \times 12.56 \\ = 0.628cm$
I hope this answer helps you