Mathematics for IGCSE & O level - Geometrical Terms (Section 2 - No. 48)
If a sector of a circle has an angle of 60 degrees at the center, and the arc length is 4.2 cm, what is the approximate length of the circumference?
12.6 cm
25.2 cm
21.0 cm
28.4 cm
คำอธิบาย
Since 60 degrees is 1/6 of 360 degrees, the circumference is 6 * 4.2 cm = 25.2 cm