The circumference of any circle is the total length of its boundary which can be calculated by the formula:
Circumference of a circle=
Where 'r' is the radius of the circle
For, the given circle the circumference can be find in terms of by putting some value of radius in the formula, which gives the circumference in terms of .
So, personally I would take 252 and divide it by 4. this will give you 63 which is 1/4 of the cookies. Then add that 63 three times to get a total of 189 cookies which would be your 3/4 sold. so since there is only 63 cookies left then you would go into your final problem. 3/9 is equal to 1/3, so all you would do is divide 63 by 3 and get a total of 21 cookies given to the pta.