Mathematics

An arc of a circle subtends an angle of 30° on the circumference of a circle…

An arc of a circle subtends an angle of 30° on the circumference of a circle of radius 21cm. Find the length of the arc.

  • A.
    11cm
  • B.
    22cm
  • C.
    44cm
  • D.
    66cm
Correct Answer: Option B
Explanation

θ = 30 x 2(∠ at center twice ∠ at θ)
∴ θ = 60°
Length of arc = (frac{theta}{360}times 2pi r\
=frac{60}{360}times 2 times frac{22}{7}times frac{21}{1}\

=22cm)