Question

The line segment joining A(-2,9), and B(6,3) is a diameter of a circle with centre C. The co-ordinates of C are

• A. (0, 0)
• B. (2, 6)
• C. (2, 0)
• D. (1,1)

Answer 1

The correct option is B (2, 6)

C is the midpoint of the diameter AB.
Mid-point of line joining two points $(x_1,–y_1)and(x_2,y_2)$ is $(\frac{x_1+x_2}{2},\frac{y_1+y_2}{2})$

Midpoint of A(-2,9) and B(6,3)

= $(\frac{-2+6}{2},\frac{9+3}{2})$
​​= $(\frac{4}{2},\frac{12}{2})$
=(2, 6)