The formula for this is . If the diameter is 8 the radius is 4, so filling in accordingly we have and which is and when you multiply in 3.14 you get that A = 401.92 or B above.
Well your question is a little unclear but say there is a bag of marbles containing 3 green marbles and 6 blue marbles then if you wanted to find the ratio of the green marbles it would be 3/9 or 1/3
. If the diameter is 8 the radius is 4, so filling in accordingly we have 
and 
which is 
and when you multiply in 3.14 you get that A = 401.92 or B above.
