Question 1040210: 1. Find the equation of the circle circumscribe the triangle determined by the line y=0, 2x+3y-15=0 and x-y=0
2. Determine the equation of the circle containing the points (-1,-1) , (3,-1) with the line x+2y-3=0 passing through the center.
I REALLY NEED HELP PLEASE.
Answer by ikleyn(52879)   (Show Source):
You can put this solution on YOUR website! .
1. Find the equation of the circle circumscribe the triangle determined by the line y=0, 2x+3y-15=0 and x-y=0
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The vertices of the triangle are (0,0), (7.5,0) and (3, 3).
The center of the circumscribed circle lies in the straight line x =  = 3.75.
The center is the intersection of the lines y-1.5 = -(x - 1.5) and x = 3.75.
(These lines are orthogonal bisectors of the two sides).
Hence, the center is (3.75,-0.75).
Now you find the radius.
Figure.
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