Question

In the diagram shown, m <AOC =124 and OA=10 cm. Which of the following is closest to the length of

arc ABC?

(1) 20.6
(2) 21.6
(3) 40.4
(4) 41.2
​

Answer 1

(2) 21.6

Explanation:

The segment OA is the radius of the circle

The arc of the complete circle is equivalent to its perimeter

perimeter = 2*π*radius = 2*π*10 = 62.83 cm

This arc is proportional to 360°. So, for 124°:

360°/124° = 62.83 cm/ x cm

x = 124*62.83/360

x = 21.6 cm