Circle Equations Review

These flashcards cover the equations of circles based on their centers, radii, circumferences, and areas.

What is the equation of a circle with center (2, 7) and radius 3?

(x-2)² + (y-7)² = 9

What is the equation of a circle with center (-2, -6) and radius 7?

(x+2)² + (y+6)² = 49

What is the equation of a circle with center (-1, 4) and radius 5?

(x+1)² + (y-4)² = 25

What is the equation of a circle with center (-3, 11) and radius 6?

(x+3)² + (y-11)² = 36

How do you find the radius when given the endpoints of a diameter at (0, 4) and (6, 14)?

r = √((6-0)² + (14-4)²) = √(36 + 100) = √136

What is the equation of a circle with center (2, 3) and a circumference of 18π?

(x-2)² + (y-3)² = 81

What is the equation of a circle with center (1, 1) and an area of 4π?

(x-1)² + (y-1)² = 4

What is the equation of a circle with center (2, -1) and a circumference of 32π?

(x-2)² + (y+1)² = 256

What is the equation of a circle with center (2, 3) and an area of 24π?

(x-2)² + (y-3)² = 24