Which is an equation of a circle with center (-5, -7) that passes through the point (0, 0)?

(x - 5)2 + (y - 7)2 = 37
(x - 5)2 + (y - 7)2 = 74
(x + 5)2 + (y + 7)2 = 74
(x + 5)2 + (y + 7)2 = 37

Question

Which is an equation of a circle with center (-5, -7) that passes through the point (0, 0)?

(x - 5)2 + (y - 7)2 = 37
	(x - 5)2 + (y - 7)2 = 74
	(x + 5)2 + (y + 7)2 = 74
	(x + 5)2 + (y + 7)2 = 37

geerky42 · Answer

Form of circle equation is $$(x-h)^2+(y-k)^2=r^2$$

geerky42 · Answer

Where $(h,k)$ is center and $r$ is radius

geerky42 · Answer

You can use distance formula (without square root) to find $r^2$:

$$d^2 = (x_1-x_2)^2+(y_1-y_2)^2$$

geerky42 · Answer

You can have $(x_1,y_1) = (-5,-7)$ and $(x_2,y_2) = (0,0)$

geerky42 · Answer

So you would have this after plugging in:

$$d^2 = (-5-0)^2+(-7-0)^2 = \cdots~?$$