OS Question 2
A circle has a centre C (1,3)The end points of a diameter of the circle are A (-3,2k) and B (5,k)
Find the value of k, k

k = 2

Step-by-step explanation:

We'll need the Midpoint Formula:  the midpoint of a segment joining points .  In other words, average the x's, then average the y's.

The midpoint of a diameter is the centre of the circle!

The midpoint of the segment joining (-3, 2k) and (5, k) is

That last expression is the centre of the circle; it is the same as (1, 3).