Tentukanlah luas dan keliling bangun lingkaran

berikut I
1.14 cm
2.20 cm
3.28 cm
4.21 cm dan 21 cm
tolong di bantu y

Tentukanlah luas dan keliling bangun lingkaran

Jawaban:

$1.)L = πr² = frac{22}{7} times 14 times 14 = 22 times 2 times 14 = 616 : {cm}^{2} \ K = 2πr = 2 times frac{22}{7} times 14 = 2 times 22 times 2 = 88 : cm : : : :$

$2.)L = πr² = 3.14 times 20 times 20 = 1256 : {cm}^{2} \ K = 2πr = 2 times 3.14 times 20 = 125.6 : cm$

$3.)L = πr² = frac{22}{7} times 28 times 28 = 22 times 4 times 28 = 2464 : {cm}^{2} \ K = 2πr = 2 times frac{22}{7} times 28 = 2 times 22 times 4 = 176 : cm : : : : :$

$4.)L = πr² = frac{22}{7} times 21 times 21 = 22 times 3 times 21 = 1386 : {cm}^{2} \ K = 2πr = 2 times frac{22}{7} times 21 = 2 times 22 times 3 = 132 : cm : : : : :$