Question

The coordinates of one end point of a diameter of a circle are (3, 5). If the co-ordinates of the centre be (6, 6), find the co-ordinates of the other end of the diameter.

Answer 1

Let the other end be (x, y),

Since the centre (6, 6) is the midpoint of the diameter,

`(3 + x) / 2 = 6 and (5 + y) / 2 = 6`

So,

⇒ 3 + x = 12 

x = 12 − 3

∴ x = 9

⇒ 5 + y = 12

y = 12 − 5

∴ y = 7

Hence, the other end of the diameter is (9, 7).