Respuesta :
Answer: [tex](x-9)^2 + (y-12)^2 = 225\\\\[/tex]
This is the same as writing (x-9)^2 + (x-12)^2 = 225
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Explanation:
Any circle equation fits the template of [tex](x-h)^2 + (y-k)^2 = r^2\\\\[/tex]
The center is (9,12) which tells us the values of h and k in that exact order.
h = 9
k = 12
To find the radius r, we need to find the distance from the center (9,12) to a point on the circle. The only point we know on the circle is the origin (0,0).
Apply the distance formula to find the distance from (9,12) to (0,0)
[tex]d = \sqrt{ (x_1-x_2)^2+(y_1-y_2)^2}\\\\d = \sqrt{ (9-0)^2+(12-0)^2}\\\\d = \sqrt{ (9)^2+(12)^2}\\\\d = \sqrt{ 81+144}\\\\d = \sqrt{ 225}\\\\d = 15\\\\[/tex]
The distance from (9,12) to (0,0) is 15 units. Therefore, r = 15
An alternative to finding this r value is to apply the pythagorean theorem. The distance formula is effectively a modified version of the pythagorean theorem.
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Since h = 9, k = 12 and r = 15, we can then say:
[tex](x-h)^2 + (y-k)^2 = r^2\\\\(x-9)^2 + (y-12)^2 = 15^2\\\\(x-9)^2 + (y-12)^2 = 225\\\\[/tex]
which is the equation of this circle.
