Step-by-step 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
