I need an A please

Question

Points (–7, 4) and (1, 8) are endpoints of the diameter of a circle. (a) What is the length of the diameter? Give the exact answer, simplified as much as possible. Show work. (b) What is the center point C of the circle? (c) Given the point C you found in part (b), state the point symmetric to C about the x-axis.

Answer 1

(a) the diameter is sqrt( (-7 - 1)^2 + (8-4)^2) = sqrt( 64 + 16) = sqrt(80) = 4*sqrt(5)

(b) the center is at the midpoint which is (-3,6)

the radius us then 2*sqrt(5), which forces the equation of the circle to be (x+3)^2 + (y-6)^2 = 20

symmetric to the center about the x-axis is (-3,-6)