Question

The vertices A and D of square ABCD lie on positive side of x and y-axis respectively. If the vertex C is the point (12, 17), then the coordinate of vertex B are

• A. (14, 16)
• B. (15, 3)
• C. (17, 5)
• D. (17, 12)

Answer 1

Answer: (C)

(17, 5)

Answer 2

Let the co-ordinate of B be (h, k)

Draw BL and CM perpendicular to x-axis and y-axis.

∴ $a\cos\theta = CM = OD = AL = 12$

and $a\sin\theta = DM = OA = BL = 5$

∴$k = BL = DM = OM - OD = 17 - 12 = 5$

∴ $h = OL = OA + AL = 5 + 12 = 17$

Hence, Point B is (17, 5)