Donald W. answered • 03/07/22
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The standard form for the equation of a circle is (x-h)2 + (y-k)2 = r2, where (h,k) is the coordinates of the center and r is the radius. We already know that the origin is (0,0), so we just need to calculate the radius. We know the circle passes through the point (-6,2), so we can use the formula for the distance between two points to get r2:
r2 = (0+6)2+(0-2)2
r2 = 40
So the final equation for this circle is x2 + y2 = 40.
Brenda D.
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Agreed looks the formula you have in your first sentence for the Standard Form of a circle is correct but the one in the calculation for radius squared does contain the radical in it. It looks like there is a typo in your calculation.
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03/08/22
Donald W.
Oops, you're right, I don't need that radical in the distance formula. I'm too used to using it to calculate distance rather than distance-squared. The final equation of the circle is still correct though, as we need distance-squared for the right hand side. I didn't actually take the square root when I did the calculations.
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03/08/22
Mark M.
Your formula should not have the radical.03/07/22