V = pi x R^2 x height
V= pi x 6^2 x 12
V= 432 pi (m^3)
Assuming n is the number of signers.
7 is 10% of y.
7 = 0.1y
y = 70
n is 80% of y
n = 0.8y
n = 0.8(70)
n = 56
56 signers
One vertex the rectangle lies on the straight line x + y = 6, which means that the sum of lengths of two adjacent sides is 6. Then the perimeter is 12 cm.