Antwort
r = Radius
d = Durchmesser
U = Umfang
A = Kreisfläche
a)
r (2,4m) × r (2,4m) × pi (3,14) = A
r (2,4m) × 2 × pi (3,14) = U
b)
U (22cm) ÷ pi (3,14) = d
d ÷ 2 = r × r × pi (3,14) = A