Question

The circumference of a circle with a diameter 1.8cm take pie to be 3.142

Answer 1

The formula to get the circumference is 2πr, π being pi and r being your radius.

Your r is 0.9 since the radius is half the diameter.

2πr = 2 x 3.142 x 0.9

= 5.6556cm

≈ 5.7cm