Question

Hitunglah keliling lingkaran yang memiliki
a.jari jari 7 cm
b.jari jari 50 cm
c.diameter 21 cm
d. diameter 10 cm
e. luas 314 cm
f. luas 616 cm

Answer 1

A.2phiR
  =2.22/7.7
  =44

Answer 2

A. K= 2πr
K= 2 x 22/7 x 7
K = 44

b. K = 2πr
K = 2 x 3,14 x 50
K = 6,28 x 50
K = 314

c. K = πd
K = 22/7 x 21
K = 66

d. K = πd
K = 3,14 x 10
K = 31,4

e. L= πr²
314 = 3,14 x r²
r² = 314/ 3,14
r² = 100
r= √100
r = 10

K= 2πr
K = 2 x 3,14 x 10
K = 62,8

f. L = πr²
616 = 22/7 x r²
r² = 616/ 22/7
r² = 196
r = √196
r = 14

K = 2πr
K = 2 x 22/7 x 14
K = 88