hitunglah keliling lingkaran jika diketahui tolong bantu•

a. r = 49 m
K = 2 (phi) r
= 2 × 22/7 × 49 >>> 49 dicoret dengan 7
= 2 × 22 × 7
= 44 × 7
= 308 m

b. r = 21 m
K = 2 (phi) r
= 2 × 22/7 × 21 >>> 21 dicoret dengan 7
= 2 × 22 × 3
= 44 × 3
= 132 m

c. r = 5 cm
K = 2 (phi) r
= 2 × 3,14 × 5
= 10 × 3,14
= 31,4 cm

d. r = 10,5 cm
K = 2 (phi) r
= 2 × 22/7 × 10,5
= 2 × 22 × 1,5
= 44 × 1,5
= 66 cm

e. r = 10,5 cm
K = 2 (phi) r
= 2 × 22/7 × 10,5 >>> 10,5 dicoret dengan 7
= 2 × 22 × 1,5
= 44 × 1,5
= 66 cm

f. d = 70 cm
K = (phi) d
= 22/7 × 70 >>> 70 dicoret dengan 7
= 22 × 10
= 220 cm

g. d = 2,8 cm
K = (phi) d
= 22/7 × 2,8
= 22 × 0,4
= 8,8 cm

h. d = 15 m
K = (phi) d
= 3,14 × 15
= 47,1 m

i. d = 50 cm
K = (phi) d
= 3,14 × 50
= 157 cm

j. d = 2,4 cm
K = (phi) d
= 3,14 × 2,4
= 7,536

Semoga bermanfaat ^_^