Question

The radius of the circle passing through the foci of the ellipse $\frac{x^2}{16}+\frac{y^2}{9}=1$ and having its centre at $(0,3)$ is ___________.

• A. $6$
• B. $4$
• C. $3$
• D. $2$

Answer 1

The correct option is B $4$

$ae=\sqrt{7}$
$r=\sqrt{{ae}^2+b^2}$
$=\sqrt{7+9}=4$