Pake cara ya bantu ku jawab dong​

No 1

a

K = 2πr

K = 2 × 22/7 × 7

K = 44 cm

b

K = 2πr

K = 2 × 3,14 × 20

K = 125,6 cm

c

K = 2πr

K = 2 × 22/7 × 21

K = 132 cm

No 2

a

K = 2πr

132 = 2 × 22/7 × r

r = 132×7/44

r = 21 cm

d = 2r

d = 2 × 21

d = 42 cm

b

K = 2πr

880 = 2 × 22/7 × r

r = 880×7/44

r = 140 cm

d = 2r

d = 2 × 140

d = 280 cm