Diketahui koordinat titik P(2, -1), Q(2, 5),dan R(4,-2). Jika a = PQ dan b = QR hasil 1/2 a + b =

PQ = OQ - OP
= (2,5) - (2,-1)
= (0,6)
QR = OR - OQ
= (4,-2) - (2,5)
= (2,-7)
1/2 x (a+b)
= 1/2 x ((0,6) + (2,-7))
= 1/2 x (2,-1)
= (1,-1/2)
sebisa saya.