Warmup 10-2 For 1-2, write an equation of a circle in standard form for the given information. 1. Center = (7, 0) and r = 4  3 2. Center = (8, -3) and r = 13 For the following circle equations, identify the center and radius. 3. (x - 7) 2 + (y + 3) 2 = Solve by completing the square. Show work! x x - 26 = 0

Examples – Circles in Standard Form Part 2 Standard Form for a Circle Equation: (x - h) 2 + (y – k) 2 = r 2 center of circle is (h, k) (opposite of each number in parenthesis) Use completing the square to write a circle equation in standard form. Then identify the center, radius, and diameter of the circle: Ex. x 2 -12x + y = 0Ex. x 2 + y 2 + 8y – 105 = 0 Ex. x x + y 2 – 39 = 0Ex. x 2 + y 2 – 6y - 72 = 0

Circles in Standard Form Practice(Part 2) In the following problems, use completing the square to write the circle equation in standard form. THEN, LIST the Center, Radius, and Diameter. Show work! 1. x 2 - 4x + y 2 – 21 = 02. x 2 + y y – 36 = 0 3. x 2 + y 2 – 10y - 56 = 04. x 2 + 6x + y = 0 5. x x + y = 06. x 2 + y y + 96 = 0 7.x 2 – 2x (y + 4) 2 = 0 8. (x - 6) 2 + y 2 – 16y = 0 9. (x + 5) 2 + y 2 – 14y + 13 = x x – 96 + (y – 9) 2 = (x – 12) 2 + y 2 + 4y - 5 = x x (y + 3) 2 = 0