Question

Consider a circle with center (2,-3) that passes through the point (5,4).

What is the equation of the described circle?
A) (x - 2)^2 + (y + 3)^2 = 58
B) (x - 2)^2 + (y + 3)^2 = 68
C) (x + 2)^2 + (y - 3)^2 = 58
D) (x + 2)^2 + (y - 3)^2 = 68

If the circle passes through the point (6,5), what is the equation of the new circle with the same center?
A) (x + 2)^2 + (y - 3)^2 = 80
B) (x + 2)^2 + (y - 3)^2 = 90
C) (x - 2)^2 + (y + 3)^2 = 80
D) (x - 2)^2 + (y + 3)^2 = 90

Answer 1

Answer: Part A: A. Part B: C

Explanation:

Substitute the number into the equation of circle: (x-h)^2 + (y-k)^2=r^2

h and k are 2, -3 so you will need to change their signs.

The final thing you will do is to find the distance of center to point. Using distance formula and you will able to find the radius. Square your radius then the result will be there