Standard Form of Circles

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

• (x – h)² + (y – k)² = r²

• (x + h)² + (y + k)² = r²

• x² - y² = r²

• x² + y² = r²

What is the equation of a circle in standard form with center at the origin?

• x + y =r²

• x - y = r²

• x² + y² = r²

• x² - y² = r²

Which of the following equations of circle in standard form with center at (1, 2) and a radius of 3 units?

• x² + y² = 3

• x² + y² = 9

• (x - 1)² + (y - 2)² = 9

• (x + 1)² + (y + 2)² = 9

Write the equation of the circle graphed above.

• (x-2)²+(y+2)²=9

• (x+2)²+(y-2)²=9

• (x-2)²+(y+2)²=3

• (x+2)²+(y-2)²=3

Which of the following equations of circles in standard form with center at (-3, 4) and a radius of 5 units?

• x² - y² = 25

• x² + y² = 25

• (x - 3)² + (y + 4)² = 25

• (x + 3)² + (y - 4)² = 25

Select the equation of a circle that has a diameter of 12.

• (x-6)²+(y+6)²=12

• (x-12)²+(y-2)²=6

• (x+1)²+(y-12)²=144

• (x-4)²+(y-1)²=36

Which of the following equations of circles in standard form with center at (-5, -8) and a radius of 6 units?

• (x - 5)² - (y - 8)² = 36

• (x + 5)² - (y + 8)² = 36

• (x + 5)² - (y + 8)² = 36

• (x + 5)² + (y + 8)² = 36

Select all equations that have a radius of 3.

• (x-3)²+(y-3)²=3

• (x+6)²+(y-2)²=9

• (x+5)²+y²=6

• (x-7)²+(y-1)²=9

• (x-2)²+(y-3)²=6

Which of the following equations of circle in general form given the center at (0, 0) and radius of 3 units?

• x² - y² = 9

• x² + y² = 9

• x² + y² - 9 = 0

• x² + y² + 9 = 0

What is the center and the radius of x² + y² = 9?

• (0, 0); r = 81units

• (0, 0); r = 9 units

• (0, 0); r = 3 units

• (0, 0); r = -3 units