4 x 7 is 28, and 8 x 7 is 56. You can use 4 x 7 to find 8 x 7 by multiplying that first and doubling that quotient.
Half of 56 is 28, therefore doubling that allows us to find the quotient of 8 x 7.
Common difference = 0.75
Next term = -0.75 + 0.75 = 0
64=2^6, 72=2^3*3^2
gcd (64,72)=8
Therefore 64/8 =8
72/8=9
gcd (8,9) =1
8,9 are relatively prime.
Thus, 64/72=8/9
Answer: 3.14 *16.8*16.8*16.9=14977.3478
14977.3478= 14,977.35
