Question

Write an equation of a circle whose

center is (-1,3) and passes through the
point (7,-2).

Answer 1

Answer: (x + 1)^2 + (y - 3)^2 = 65

Explanation:

Answer 2

Answer: (x+1)²+(y-3)²=89

Explanation:

An equation of a circle: (x-a)²+(y-b)=R²

The center of a circle is (-1,3), hence a=-1 b=3

(x-(-1))²+(y-3)=R²

(x+1)²+(y-3)²=R² (1)

Substitute the coordinate (7,-2) belonging to the circle into equation (1):

(7+1)²+(-2-3)²=R²

8²+(-5)²=R²

64+25=R²

89=R²

Thus, R²=89

Hence,

(x+1)²+(y-3)²=89