10-8 Equations of Circles (Flashcardizz)

Front

What is the standard 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 are the coordinates of the center of the circle in the equation (x+2)²+(y-4)²=41?

Back

(-2, 4)

Front

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

Back

5 units (since r² = 25, r = √25 = 5).

Front

What is the diameter of a circle if the radius is 2 units?

Back

4 units (Diameter = 2 * Radius).

Front

What is the center of the circle in the equation x² + y² = 9?

Back

(0, 0) (the center is at the origin).

Front

What is the equation of a circle with center (3, -2) and radius 4?

Back

(x-3)² + (y+2)² = 16 (since r² = 4² = 16).

Front

What is the radius of the circle described by the equation (x+1)² + (y-1)² = 9?

Back

3 units (since r² = 9, r = √9 = 3).

Front

In the equation (x-5)² + (y+3)² = 36, what is the center of the circle?

Back

(5, -3)

Front

What is the equation of a circle with center (0, 0) and radius 7?

Back

x² + y² = 49 (since r² = 7² = 49).

Front

What is the center of the circle in the equation (x-1)² + (y+4)² = 25?

Back

(1, -4)