Question

The daimeter of a circle whose circumfrence is 30.8

Answer 1

circumference=
$2\pi \times r$
$2 \times 22 \div 7 \times r = 30.8$
44r/7=308/10
440r=308×7
440r=2156
r=2156/440=4.9
diameter =2r
so, diameter=2×9.4=18.8