Question

A circle is centered at the point (-7, -1) and passes through the point (8, 7). The radius of the circle is 13 units. The point (-15, y ) lies on this circle.
find Y

Answer 1

The standard form of the equation of circle is:

(x – h)^2 + (y – k) ^2 = r^2 

Where the center being at the point (h, k) and the radius being r

Substituting the values to the equation:

(-15 - (-7)) ^2 + (y – (-1)) ^2 = 13^2 

64 + (y +1) ^2 = 169

(y +1) ^2 = 105

y + 1 = 10.247

y = 9.247