Question

Oblcz pole kola jesli obwod wynosi
A 22 pi cm
B 36 pi cm
C 2 pi dm
D 13,4 pi m
E 0,6 pi m

Answer 1

Obw. = 2πr
P = πr²

A.
2πr = 22π cm    /:2π
r = 11 cm

P = πr² = π * (11cm)² = 121π cm²

B.
2πr = 36π cm    /:2π
r = 18 cm

P = π * (18cm)² = 324 cm²

C.
2πr = 2π dm      /:2π
r = 1 dm

P = πr² = π * (1dm)² = π dm²

D.
2πr = 13,4π m      /:2π
r = 6,7 m

P = πr² = π * (6,7m)² = 44,89π m²

E.
2πr = 0,6π m      /:2π
r = 0,3 m

P = πr² = π * (0,3m)² = 0,09π m²