SOLUTION: a circle of radius 5 units has its center in the first quadrant, touches the x-axis and the intercepts a chord of length 6 units on the y-axis. find the equation of this circle

Algebra ->  Quadratic-relations-and-conic-sections -> SOLUTION: a circle of radius 5 units has its center in the first quadrant, touches the x-axis and the intercepts a chord of length 6 units on the y-axis. find the equation of this circle      Log On


   



Question 1042865: a circle of radius 5 units has its center in the first quadrant, touches the x-axis and the intercepts a chord of length 6 units on the y-axis. find the equation of this circle
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
If the center is at (h,k) and radius = +r+ then
the equation is +%28+x-h+%29%5E2+%2B+%28+y-k+%29%5E2+=+r%5E2+
Since it touches the x-axis, +k+=+r+
and it's given +r+=+5+, so
+%28+x+-+h+%29%5E2+%2B+%28+y+-+5+%29%5E2+=+5%5E2+
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If the radius bisects the chord on the y-axis, that
radius is parallel to the x-axis. 1/2 of the chord = +3+.
+r+=+5+. This forms a 3-4-5 right triangle, so the center
of the circle is +4+ units from the y-axis, so +h+=+4+
Now I have: +%28+x+-+4+%29%5E2+%2B+%28+y+-+5+%29%5E2+=+25+
Here it is plotted: