An important word that is used in circle theorems is subtend . An angle is created by two lines. The angle in between the two lines is subtended by the arc between C and D.

The arc length is 1 4 × π × 8 = 2 π. Rounded to 3 significant figures the arc length is 6.28cm. The formula to calculate the arc length is: Arc length = angle 360 ∘ × π × d ...