Question

The endpoints of a diameter of a circle are (-4, 9) and (8, -7).

Find the center and radius of the circle.
Write the standard equation of the circle.

Answer 1

Explanation:

The centre which is the mid point is x1 + X2/2. and y1+y2/2

which give -4+8/2 =2 i.e X= 2

and 9+(-7)/2 = 9-7/2 = 1

therefore, the centre is (2,1)

the radius is √x2-x1)^2 + (y2-y1)^2

= √-4-2)^2+(9-1)^2

=√36+64 =√100

= 10 units