Jawab:= 650 (lingkaran)
Penjelasan :Diketahui pola2 6 12 20maka,a = 2, 6, 12, 20b = +4+6+8c = +2 +2
a = 2, b = 4, c = 2Pola 25, n = 25
Un = a+b(n-1)+c(n-1)(n-2)/2U₂₅ = 2+4(25-1)+2(25-1)(25-2)/2U₂₅ = 2+4(24)+2(24)(23)/2U₂₅ = 2+4(24)+(24)(23)U₂₅ = 2+24(4+23)U₂₅ = 2+24(27)U₂₅ = 2+648U₂₅ = 650 (lingkaran)
(xcvi)