Tentukan keliling dan luas lingkaran berukuran sebagai berikut: A. jari-jarinya 3,5 cm B. jari-jarinya 4 cm C. jari-jarinya 5,6 cm D. jari-jarinya 7 cm

a.k= 22 cm
L= 38,5 cm2

b.k=25,12 cm
L= 200,96 cm2

c.k= 35,2 cm
L= 98,56 cm2

d.k= 44 cm
L= 154 cm2

rumus Luas Lingkaran=π×r×r
rumus Keliling Lingkaran= 2×π×r

A.
Keliling=
[tex]2 \times \frac{22}{7} \times 3.5 \\ 2 \times 22 \times 0.5 = 2 \times 11 = 22cm[/tex]
Luas=
[tex] \frac{22}{7} \times 3.5 \times 3.5 = 22 \times 0.5 \times 3.5 = 11 \times 3.5 = 38.5 {cm}^{2} [/tex]
B.
Keliling=
2×3,14×4=6,28×4=25,12cm
Luas=3,14×4×4=50,24cm2

C.
Keliling=
[tex]2 \times \frac{22}{7} \times 5.6 \\ 2 \times 22 \times 0.8 = 44 \times 0.8 = 35.2cm[/tex]
Luas=
[tex] \frac{22}{7} \times 5.6 \times 5.6 \\ = 22 \times 0.8 \times 5.6 \\ = 98.56 {cm}^{2} [/tex]
D.
Keliling=
[tex]2 \times \frac{22}{7} \times 7 = 22 \times 2 = 44cm[/tex]
Luas=
[tex] \frac{22}{7} \times 7 \times 7 = 22 \times 7 = 154 {cm}^{2} [/tex]