Equation of a Circle

Front

What is the standard equation of a circle with center (h, k) and radius r?

Back

(x - h)² + (y - k)² = r²

Front

What is the center of the circle in the equation (x - 3)² + (y + 4)² = 121?

Back

(3, -4)

Front

What is the radius of the circle in the equation (x + 2)² + (y - 3)² = 4?

Back

2

Front

How do you find the radius from the equation (x - 5)² + (y + 1)² = 36?

Back

The radius is √36 = 6.

Front

What does the equation x² + y² = 25 represent?

Back

A circle centered at the origin (0, 0) with a radius of 5.

Front

If a circle has a diameter of 24, what is its radius?

Back

12 (radius is half of the diameter).

Front

What is the equation of a circle with center (0, 0) and radius 10?

Back

x² + y² = 100.

Front

In the equation (x - 1)² + (y - 2)² = 9, what is the center of the circle?

Back

(1, 2)

Front

What is the general form of a circle's equation?

Back

x² + y² + Dx + Ey + F = 0.

Front

How do you convert the general form of a circle to standard form?

Back

Complete the square for x and y.