Equations of Circles

Front

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

Back

x² + y² = r²

Front

What is the radius of the circle given by the equation (x-h)² + (y-k)² = r²?

Back

The radius is r.

Front

In the equation (x-h)² + (y-k)² = r², what do h and k represent?

Back

h and k represent the x and y coordinates of the center of the circle.

Front

What is the center of the circle in the equation (x+4)² + (y-3)² = 25?

Back

The center is (-4, 3).

Front

Write the equation of a circle with center (2, -5) and radius 4.

Back

(x - 2)² + (y + 5)² = 16.

Front

What is the equation of a circle with center (0,0) and radius 5?

Back

x² + y² = 25.

Front

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

Back

The radius is √36 = 6.

Front

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

Back

(x-h)² + (y-k)² = r².

Front

If the equation of a circle is (x-3)² + (y+1)² = 49, what is the radius?

Back

The radius is 7.

Front

What is the center of the circle in the equation (x-5)² + (y+2)² = 9?

Back

The center is (5, -2).