Question

A circle is centered at the point (-7,-1) and passes through the point (8, 7). The radius of the circle is ___ units. The point (-15, __ ) lies on this circle

Answer 1

(x + 7)2 + (y + 1)2 = r2.

To get we use point (8, 7): (8 + 7)2 + (7 + 1)2 = r2, r2 = 225 + 64 = 289 = 172.

So, equation of circle: (x + 7)2 + (y + 1)2 = 289

Explanation: