Question

Consider a sphere passing through the origin and the points $(2,1,-1),(1,5,-4),(-2,4,-6)$. What is the radius of the sphere?

• A. $\sqrt{12}$
• B. $\sqrt{14}$
• C. $12$
• D. $14$

Answer 1

The correct option is B $\sqrt{14}$

Equation of sphere is

$x^2+y^2+z^2+2x-4y+6z=0$

Put the value $(0,4,0)$, we get

$0+16+0+0-16+0=0$

So the sphere passes through the point $(0,4,0)$

Thus radius of sphere is $\sqrt{1}4$