DIKETAHUI TUTUP DRUM BERJARI JARI 20CM. BERAPAKAH KELILING DAN LUAS TUTUP DRUM?

K = 2πr
K = 2 . 3,14 . 20
K = 125,6 cm

L = πr²
L = 3,14 . 20 . 20
L = 1.256 cm²

[tex]k = 2 \times \pi \times r \\ \: \: \: = 2 \times 3.14 \times 20 \\ \: \: \: = 2 \times \frac{314}{100} \times 20 = \frac{2 \times 314 \times 20}{100} = 125.6cm[/tex]
[tex]l = \pi \times {r}^{2} \\ \: = 3.14 \times {20}^{2} \\ = \frac{314}{100} \times 400 \\ = 314 \times 4 \\ = 1256 {cm}^{2} [/tex]

maap klo salah