1)
A = 2 * (1/2 * r^2) + 2 * (r^2 - 1/4 * pi * r^2)
Einsetzen
A = 2 * (1/2 * 20^2) + 2 * (20^2 - 1/4 * pi * 20^2) = 571.7 mm^2
U = 2 * (√(2 * r^2)) + 2 * (1/4 * 2 * pi * r)
Einsetzen
U = 2 * (√(2 * 20^2)) + 2 * (1/4 * 2 * pi * 20) = 119.4 mm
2)
p% = 571.7 / (4 * 20^2) = 0.3573 = 35.73%