CircleHardBloom L3
Question
A square $OABC$ is formed by line pairs $xy = 0$ and $xy + 1 = x + y$ where ' $O$ 'is the origin. A circle with centre $C_{1}$ inside the square is drawn to touch the line pair $xy = 0$ and another circle with centre $C_{2}$ and radius twice that of $C_{1}$, is drawn to touch the circle $C_{1}$ and the other line pair. The radius of the circle with centre $C_{1}$ is:
Options
A.$\frac{\sqrt{2}}{\sqrt{3}(\sqrt{2} + 1)}$
B.$\frac{2\sqrt{2}}{3(\sqrt{2} + 1)}$
C.$\frac{\sqrt{2}}{3(\sqrt{2} + 1)}$
D.$\frac{\sqrt{2} + 1}{3\sqrt{2}}$
Solution
[Key Concept: From the line-pairs $xy = 0$ and $xy + 1 = x + y$ find the square's vertices, then read the property.]
$C_{1},C_{2}$ lie on $y = x$ line
$$\begin{matrix} OB = OC_{1} + C_{1}C_{2} + \\ \sqrt{2} = r\sqrt{2} + 3r + 2r \\ \ r = \frac{\sqrt{2}}{3(\sqrt{2} + 1)} \end{matrix}$$
Create a free account to view solution
View Solution FreeMore Circle Questions
The tangent drawn from the origin to the circle $x^{2} + y^{2} + 2gx + 2fy + f^{2} = 0$ are perpendicular, if:...The equation of the pair of tangents drawn to the circle x2 + y2 − 2x + 4y + 3 = 0 from (6, − 5) is-...Consider the equation of a parabola y2 = 4ax, (a < 0) which of the following is false -...Consider a family of circles which are passing through the point (-1, 1) and are tangent to xaxis. If (h, k) are the co-...The eccentric angle of the point where the line, 5x - 3y = 8 √2 is a normal to the ellipse = 1 is -...