Circle Graph Help, what is the radius for this problem?
I am working on my math homework, it is due soon and there are no tutoring hours available between now and then.
Write the standard equation for the circle centered at (-3,9) which passes through the origin.
HINT: Every point on the circle is the exact same distance from the circle's center.
I have:
(x+3)^2 + (y-9)^2 = r^2
The hint is throwing me. But it really is just explaining what a radius is, correct?
3 replies
At a guess that hint is there to help you "check your work". You know how far the center is from the point using Pythagorean theorem (I assume). So you can put 0, 0 into your equation and verify that the number you get as the radius is the same as from your triangle.
I got help from the SI on this today. The passes through the origin was supposed to be a clue that the radius was at (0,0). So my equation was nearly correct, but I still needed to calculate the radius.
Which basically I think is what you were saying.
Sounds like it. I’m not sure what the hint is even there for, isn’t that how a circle works? As opposed to some other shape….