Hello from MrBillDoesMath!
Answer: radius = 20
Discussion:
The distance between two complex points z1 ( = x1 + i y1) and z2 ( = x2 + iy2) is
sqrt ( (x1-x2)^2 + (y1-y2)^2)
In our case z1 = -10 - 1i and z2 = 6 + 11i. Per the above formula, the distance, or radius of the circle, is given by
sqrt ( (-10 - 6)^2 + ( -1 - 11)^2 ) =
sqrt ( ( -16)^2 + (-12)^2) ) =
sqrt ( 256 + 144) =
sqrt(400) =
20
Thank you,
MrB
