Question

cotton thread is wound on a reel which has a diameter of 2.8 CM. There are 1200 turns of the thread on the reel. what is the total length in metres of the thread on the reel.

Answer 1

$1200 \div 2.8 = 1200 \times 10 \div 28 = 600 \times 5 \div 7 = 3000 \div 7 = 428.57 \div 1000 = .42857$