MATHEMATICS

JAMB 2003 - Question 23

Mathematics 2003 JAMB Past Questions - Question 23: 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.

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:
B:
C:
D:
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Correct Answer

A

Explanation

To find the length of the arc, we can use the formula:Length of arc = (θ/360) * 2πrwhere θ is the angle subtended by the arc, r is the radius of the circle, and π is a mathematical constant approximately equal to 3.14159.Given that the angle θ is 30 degrees and the radius r is 21 cm, we can substitute these values into the formula:Length of arc = (30/360) * 2π * 21Simplifying the expression:Length of arc = (1/12) * 2π * 21Length of arc = (1/6) * π * 21Length of arc = (7/2) * πApproximating the value of π to 3.14159, we have:Length of arc ≈ (7/2) * 3.14159Length of arc ≈ 10.9956 cmTherefore, the length of the arc is approximately 10.9956 cm.