nomor 18 sekalian caranya pls... :)

lingkaran

luas juring = alfa/360 * phi r²
48 = 72/360 * 22/7 * r²
48 = 1/5 * 22/7 r²
r² = 840/11

luas juring POS
= 96/360 * 22/7 * 840/11
= 4/15 * 240
= 64 cm²

jawaban C