What is the length of circumference of a circle with centre O and diameter 9.8 mm?

9.8π mm

Concept Used

Circumference = 2 x (\(\frac{22}{7}\)) x r   [r = radius of circle]

Calculations

Let radius of circle = r mm

According to the questions,

= 2 x r = 9.8

= r = 4.9

Therefore, circumference = 2 x (\(\frac{22}{7}\)) x 4.9 = 9.8\(\pi \) mm

Therefore, answer is 9.8\(\pi \) mm.