Question

Write an equation of a circle that has the center at the origin and goes through (-3,-6)

Answer 1

Answer:

$x^{2} +y^{2} = 45$

Step-by-step explanation:

General Equation of circle is

$(x-x_1)^{2} +(y-y_1)^{2} = r^{2}$----------- (1)

Here

$(x_1, y_1)= (0, 0)$

Radius r is distance from origin (x1, y1) to point (x2, y2)=(-3, -6)

$r=\sqrt{(x_2-x_1)^{2} + (y_2-y_1)^{2} }$

$r= \sqrt{(-3-0)^{2} + (-6-0)^{2} }$

$r= \sqrt{9+36}$

$r=\sqrt{45}$

Substituting values in equation (1)

$(x-0)^{2} +(y-0)^{2} =( \sqrt{45})^{2}$

$x^{2} +y^{2} = 45$