Question

Which of the following is the equation of a circle whose center is at the origin and whose diameter has endpoints (-1, 2) and (1, -2)?
a. x2+y2= 2
b. x2+y2= 3
c. x2+y2= 4
d. x2+y2= 5

Answer 1

the distance between the two points is the diamater, so half that distance is the radius.

Answer 2

c