Practice Equation of a Circle

Front

What is the standard form of the equation of a circle?

Back

(x - h)² + (y - k)² = r², where (h, k) is the center and r is the radius.

Front

What does the center of a circle represent in its equation?

Back

The center (h, k) is the point from which all points on the circle are equidistant.

Front

How do you find the radius from the equation of a circle?

Back

The radius is the square root of the constant on the right side of the equation in standard form.

Front

What is the center of the circle with equation x² + y² = 1?

Back

(0, 0)

Front

What is the radius of the circle with equation x² + y² = 9?

Back

3 (since the radius is √9)