SOLUTION: How do I write the standard equation for the circle that passes through the points: (-1, 2) (4, 2) (- 3, 4)

Algebra.Com
Question 583783: How do I write the standard equation for the circle that passes through the points:
(-1, 2)
(4, 2)
(- 3, 4)

Found 2 solutions by Alan3354, solver91311:
Answer by Alan3354(69443)   (Show Source): You can put this solution on YOUR website!
How do I write the standard equation for the circle that passes through the points:
(-1, 2)
(4, 2)
(- 3, 4)
-----------
Pick 2 of the 3 lines between the 3 points and find the perpendicular bisectors of them.
--------
The intersection of the perpendicular bisectors is the center of the circle, (h,k).
The radius is the distance from the center to any of the 3 points, = r.
-->
--------------
Or use determinants.

Answer by solver91311(24713)   (Show Source): You can put this solution on YOUR website!


Use the idea that the perpendicular bisector of any chord of a circle passes through the center of the circle. Since the given points are on the circle, any pair of the three points are the endpoints of a line segment that is a chord of the circle.

Select 2 of the three given points.

Step 1: Calculate the midpoint of the segment connecting those two points using the midpoint formulas:

and



Step 2: Calculate the slope of the line containing the two selected points using the slope formula:



Step 3: Determine the slope of the perpendicular to the segment. Take the negative reciprocal of the slope calculated in step 2.

Step 4: Derive an equation of the perpendicular bisector of the selected segment by using the point-slope form of an equation, the slope from step 3, and the midpoint from step 1.



Choose a different pair of points and repeat the process.

Take the two equations of the perpendicular bisectors as a 2X2 system and solve for the point of intersection, which is the center of the circle.

Use a modified form of the distance formula to calculate the radius squared:



where is any of the initially given points.

Using the coordinates of the center and the radius, write the standard form equation:



John

My calculator said it, I believe it, that settles it
The Out Campaign: Scarlet Letter of Atheism


RELATED QUESTIONS

Hi, these are five questions which I need help in Write the general equation for the... (answered by Alan3354,Boreal,solver91311,ikleyn)
What is the standard equation for the circle that passes through the points: (-5, 0)... (answered by lwsshak3)
Write the equation in standard form for the line that passes through the points ( 4, -2 ) (answered by Edwin McCravy)
i need to find the equation of the line that passes through each pai of points and write... (answered by Alan3354)
How would I write a quadratic equation in standard form that passes through the points... (answered by ankor@dixie-net.com)
HOW DO I WRITE AN EQUATION IN STANDARD FORM FOR A LINE THAT PASSES THROUGH THESE POINTS,... (answered by checkley71)
Write the standard equation for the circle that passes through the points: (1, 7) (8,... (answered by richwmiller)
Find the equation of the circle that passes through (-2, 1), (4, -3), and... (answered by Alan3354)
Find the equation of the circle that passes... (answered by Alan3354)