Question

circumference of diameter 8 centimetre

Answer 1

circumference = 2 * π * radius

= 2 * 22/7 * 8/2

= 25.14cm

hope it's help you..

Answer 2

$circumference = 2\pi \: r \\ circumference = \frac{22 \times 4 \times 2}{7} = 25.1$
this is the accurate answer