panjang jari jari lingkaran 20cm,jika π 3.14 hitunglah panjang busur dihadapan <30° dan luas jaring dihadapan<45°

panjang busur = 30°/360° × 2 × phi × r
= 1/12 × 2 × 3,14 × 20
= 10,47 cm

L juring = 45°/360° × phi × r^2
= 1/8 × 3,14 × 20 ×20
= 157 cm^2