please jawab.....no 3 n 4

luas lingkaran = 22/7.21.21= 1386cm2
luas juring = 90/360.1386=346,5cm2
luas ∆ = 1/2.21.21=220,5cm2
lias tembereng/yang diarsir = 346,5-220,5=126cm2


good luck... be a the best... ;-)