The cross sectional area is
a = π*r^2 = π*(d/2)^2 = (π/4)*d^2
a = π/4*(15 mm)^2 = 225π/4 mm^2
a = π*r^2 = π*(d/2)^2 = (π/4)*d^2
a = π/4*(15 mm)^2 = 225π/4 mm^2
Didn't find the answer you were looking for?