Equations of Circles

                            Lesson 1

 

                                                            Problem:   Write the center-radius equation of a circle with a center at (-3,6)

                                                                                 and passes through the point (-4,7).

                                                           

                                                            Solution     The radius obtains by using the distance formula.

                                                            Step 1:         

                           

                                                            Solution     Points (-3,6) and (-4,7) were used here.(d =distance, or radius)

                                                            Step 2:            

                            

                                                            Solution     d=√(x2-x1)2+(y2-y1)2; √(-4+3)2+(7-6)2; √(1+1);√(2)

                                                            Step 3:   

 

                                                            Solution     Equation:(x+3)2+(y-6)2 = 2

                                                            Step 4:   

 

                                                            Solution     Answer: (x+3)2+(y-6)2 = 2

                                                            Step 5:   

Complete      

 

                                                            Try two practice problems:  

 

A

Write the center-radius equation of a circle with a center at (-3,4) and passes through the point (-5,6).

B

Write the standard equation of a circle that is tangent to the x-axis, with a center located at (6,-4).

 

 

 

 

 

 

 

 

 

 

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