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. r = 3,5 cm
[tex]k = 2\pi \: r \\ k = 2 \times \frac{22}{7} \times 3.5 \\ k = 22cm[/tex]
[tex]luas = \pi \: r^{2} = \frac{22}{7} \times 3.5^{2} = \frac{22}{7} \times 12.25 = 38.5 {cm}^{2} [/tex]
b. r = 4 cm
[tex]k = 2\pi \: r \\ k = 2 \times 3.14 \times 4 \\ k =25.12[/tex]
[tex]luas = \pi \: r^{2} = 3.14 \times {4}^{2} = 3.14 \times 16 = 50.16 {cm}^{2} [/tex]

c. r = 5.6 cm
[tex]k = 2\pi \: r \\ k = 2 \times 3.14 \times 5.6 \\ k =35.168cm[/tex]
[tex]luas = \pi \: r^{2} = 3.14 \times {5.6}^{2} = 3.14 \times 31.36 = 98.47 {cm}^{2}[/tex]
d. r = 7 cm
[tex]k = 2\pi \: r \\ k = 2 \times \frac{22}{7} \times 7 \\ k = 44cm[/tex]
[tex]luas = \pi \: r^{2} = \frac{22}{7} \times 7^{2} = \frac{22}{7} \times 49 = 154 {cm}^{2} [/tex]

a.
[tex]k = 2\pi {r}\\ =2 \times \frac{22}{7} \: \times 3.5 \\ = 22 \times \frac{5}{5} \\ = 22 \: cm \\ \\l = \pi {r}^{2} \\ = \frac{22}{7} 3.5 \times 3.5 \\ = 38.5 \: {cm}^{2} [/tex]
b
[tex]k = 2 \times \pi \: r \\ = 2 \times 3.14 \times 4 \\ = 25.12 \\ \\ l = \pi \: {r}^{2} \\ = 3.14 \times 4 \times 4 \\ = 50.24 \: {cm}^{2} [/tex]
c.
[tex]k = 2\pi \: r \\ = 2 \times \frac{22}{7} \times 5.6 \\ = 35.2 \\ \\ l = \pi {r}^{2} \\ = \frac{22}{7} \times 5.6 \times 5.6 \\ = 98.56[/tex]
segitu aja. maaf klo slh