SOLUTION: write an equation for the circle with the endpoints of the diameter at (-2,13) and (8,7)

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Question 143161: write an equation for the circle with the endpoints of the diameter at (-2,13) and (8,7)
Answer by solver91311(24713) About Me  (Show Source):
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Use the midpoint formulas to calculate the coordinates of the diameter midpoint. This will be the center of the circle, (h, k). Use the distance formula to calculate the distance from one of the diameter endpoints to the center you just calculated, this will be the radius, r.

Midpoint formulas:

x%5Bm%5D=h=%28x%5B1%5D%2Bx%5B2%5D%29%2F2, and y%5Bm%5D=k=%28y%5B1%5D%2By%5B2%5D%29%2F2, giving you a circle center of (h,k) .

Distance formula:

r=sqrt%28%28x%5B1%5D-h%29%5E2%2B%28y%5B1%5D-k%29%5E2%29

Once you have (h,k) and r, substitute into %28x-h%29%5E2%2B%28y-k%29%5E2=r%5E2 and you will have your equation.

Hint: Pay close attention to your signs.