Acircle is centered at the point (-3, 2) and passes through the point (1, 5). the radius of the circle is ? units. the point (-7, ? ) lies on this circle.

Hello,

The circle has like equation: (x+3)²+(y-2)²=r²

If x=1 then y=5 ==>(1+3)²+(5-2)²=r²==>4²+3²=r²==>r=5 (the radius)

if x=-7 then (-7+3)²+(y-2)²=25 ==>  (y-2)²=25-16==>y=2+3 or y=2-3
The points (-7,5) and (-7,-1) are on the circle.