Question

Algebra 2 help please!! What is the center and radius of the circle with equation x^2 + (y + 6)^2 = 49? I dont know where to start?!

Answer 1

The center is at (h,k). H and K can be found because the equation for a circle is (x-k)^2 + (y-k)^2 = r^2. Also notice how I put minus signs. Those MUST be minus signs. If they are plus signs, then it means the number in there is actually negative. so we need h, k. Notice you have x^2, but not (x-h)^2. This means that your h (which is the x-coordinate of the center of yourcircle) is just 0. As for the y, we have (y+6)^2. Like I just said, though, that must be a minus sign there. So since its a plus sign, that means it is actually (y-(-6))^2, making k (the y-coordinate of your center) at -6. As for the radius, whatever is on the other sideof the equal sign is r^2, so just take the square root of that :p Does that all make sense?

Answer 2

Sort of. so would the radius be 7 then?

Answer 3

Yes it would be 7.

Answer 4

thank you both so much!!

Answer 5

Yep, yep. Good luck :3