C=pid
d=diameter
d=4
C=4pi
tada
if you want
aprox pi=3.14
C=12.56 units
To find the percent decrease from Saturday to Tuesday, you will find the difference between the number of customers on those days and divided by the total number of customers on Saturday.
By dividing this you will get a decimal, which then can be converted to a percent.
80-17= 63
63/80 = 0.7875
0.7875 = 78.75%
There was a 78.75% decrease from Saturday to Tuesday.
Isolate the variable by dividing each side by factors that don't contain the variable.
f=e-g/d
If there are 70 chairs but only 20 rows then that means he will have to set up 3.5 chairs per row, or Brook could set up 14 rows with 5 chairs in each row.
Srry if that didn't help but that's what i got from that.