diketahui diameter 18cm.sudut pusat 140° . tentukan luas juring dan panjang busur?

Penyelesaian:
Diket.:
d = 18 cm
r = ½d = ½ × 18 = 9 cm
α = 140°
Ditanya:
Luas juring = ....?
Panjang busur = ....?
Jawab:
Luas juring
= α/360° × πr²
= 140°/360° × 22/7 × 9²
= 7/18 × 22/7 × 81
= 12.474/126
= 99 cm²

Panjang busur
= α/360° × 2πr
= 140°/360° × 2 × 22/7 × 9
= 7/18 × 396/7
= 2.772/126
= 22 cm

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