ABCD is a square in which A lies on the positive y-axis and B lies on the positive x-axis. If D is the point (12, 17), the coordinates of C are
(17, 12)
(17, 5)
(14, 16)
(15, 3)
Triangles NDA, MBC and OAB are congruent
⇒ MB = OA = ND = 12
and CM = OB = NA = ON - OA = 5
OM = OB + BM = 5 + 12 = 17
coordinates of C = (OM, CM) = (17, 5)