Circle Equations Worksheets
What Are Circle Equations? A circle is an active member of the geometrical shapes which are mostly used by mathematicians. By definition, a circle is known as the set of points on a plane which is on the same distance as the center point. In easier terms, the circle is a rounded shape with a center point which has the same distance as every point on the surface of the circle. The distance between the center and any point on the surface is called the radius. Now, just like every other geometrical figure, the circle has a set of equations for various situations. The most general form of equations is the circle which has the center present at the origin; hence, the equation becomes x^{2} + y^{2} = r^{2}, where r is the radius. However, if the center doesn't lie on the origin, then the equation of the circle becomes (xh)^{2} + (yk)^{2}2 = r^{2}, where r is the radius and (h, k) are the points of the origin. This equation is also called the standard form of the equation of a circle.

Basic Lesson
Guides students through writing the equation of a circle. Standard form equation of a Circle: On the coordinate plane, the standard form equation of a circle is: (x  h)^{2} + (y  k)^{2} = r^{2}. h and k are the x and y coordinates of the center of the circle.
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Independent Practice 1
A really great activity for allowing students to understand the concepts of the Circle Equations. Write the standard equation, the center, and the radius for each circle.
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Independent Practice 2
Students use Circle Equations in 20 assorted problems. The answers can be found below.
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Homework Worksheet
Students are provided with 12 problems to achieve the concepts of Using a Calculator (sin, cos, tan).
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Here's a cute riddle:
A circle by any other name is just
as round. How about another?
Try: Compasses travel in the best of circles!