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Learn how to write and use equations of circles in the coordinate plane. Understand the vocabulary and standard equation of a circle centered at (h, k) with a radius of r units as (x - h)^2 + (y - k)^2 = r^2. Explore examples and practice graphing circles in the plane.
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7-8 Equations of Circles • Objectives: • To write and use the equation of a circle in the coordinate plane.
Standard Equation of a Circle • In general, an equation for a circle center at (h, k) and a radius of r units is: (x – h)2 + (y – k)2 = r2 • Please note that the minus signs are part of the equation.
Example 1 • Write an equation for a circle with center C(-3, 6) and diameter of 6 units. (x – h)2 + (y – k)2 = r2
Example 2 • Graph the circle whose equation is (x + 2)2 + (y – 3)2 = 9
Homework 7-8 Worksheet