Question

Two circles with equal radii are intersecting at the points $(0, 1)$ and $(0, -1)$. The tangent at the point $(0, 1)$ to one of the circles passes through the centre of the other circle. Then the distance between the centres of these circles is :

• A. $1$
• B. $\sqrt{2}$
• C. $2 \sqrt{2}$
• D. $2$

Answer 1

Answer: (D)

$2$

Answer 2

The correct option is(D): 4.

$DC_1=\frac{\sqrt{2}r}{2}$

$=1+\frac{r^2}{2}=r^2$

$r=\sqrt2$

$C_1C_2=2$