It is because the formula for the circumference of a circle is 2 x 3.14 x r so I do the 2 x 3.14 and I get the 6.28 and then 6.28 x 3.5(radius) is 21.98.
Ok so there are 7 different options for each of the remaining 7 people to be sat in which means that the answer can be given by 7!=7*6*5*4*3*2*1=5040 different ways
