tolong ya pakai cara ^^

4.)p.busur=sudut pusat/360°×k.lingkaran
=120°/360°×2×3,14×21
=1/3×2×65,94
=1/3×131,88
=43,96 cm
k.juring=p.busur+(2×r)
=43,96+(2×21)
=43,96+42
=85,96 cm

maaf kalo sala