SOLUTION: our teacher went over notes we took but i really dont get it but the basic concept of the section is to write the standard equation of a circle then graphing it i just didnt unders

Question 134776This question is from textbook Mac Dougal Littel Geometry
: our teacher went over notes we took but i really dont get it but the basic concept of the section is to write the standard equation of a circle then graphing it i just didnt understand so if you could exsplain those two things that be great This question is from textbook Mac Dougal Littel Geometry

Answer by solver91311(24713) (Show Source): You can put this solution on YOUR website!
The standard equation for a circle with a center at the point (h,k) and radius r is .

Graphing a circle, given an equation in standard form is a simple matter of extracting the values of h and k from the equation, plotting the point (h,k) that represents the center, setting your compass to the measure of the radius (which is the square root of the value on the right side of the equation) and drawing your circle.

For example: Given

First find h: so

Next find k: so

Now you know that the center of the circle is at the point (3,-2)

Take the square root of the right side of the equation: so your radius is 5.

On the other hand, if you are given that a circle has a center at (-1,4) and a radius of 3, you can write the equation by substitution into .

If the center is at (-1,4) and the radius is 3, , , and the , so your equation is:

There are a bunch of examples of algebraic manipulations of the equation of a circle at www.analyzemath.com/CircleEq/Tutorials.html
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