Three equal circles each of radius `r` touch one another. The radius of the circle touching all the three given circles internally is `(2+sqrt(3))r` (b) `((2+sqrt(3)))/(sqrt(3))r` `((2-sqrt(3)))/(sqrt(3))r` (d) `(2-sqrt(3))r`

The radius of the circle touching the straight lines x-2y-1=0 and 3x-6y+7=0 is (A) 1/sqrt(2) (B) sqrt(5)/3 (C) sqrt(3) (D) sqrt(5)

The equation of four circles are (x+-a)^2+(y+-a2=a^2 . The radius of a circle touching all the four circles is (sqrt(2)+2)a (b) 2sqrt(2)a (sqrt(2)+1)a (d) (2+sqrt(2))a

The rationalisation factor of sqrt(3) is (a) -sqrt(3) (b) 1/(sqrt(3)) (c) 2sqrt(3) (d) -2sqrt(3)

Two equal circles of radius r intersect such that each passes through the centre of the other. The length of the common chord of the circles is sqrt(r) (b) sqrt(2)\ r\ A B (c) sqrt(3)\ r\ (d) (sqrt(3))/2\ r

The radius of the circle passing through the points (1, 2), (5, 2) and (5, -2) is : (A) 5sqrt(2) (B) 2sqrt(5) (C) 3sqrt(2) (D) 2sqrt(2)

The value of sqrt(3-2\ sqrt(2)) is (a) sqrt(2)-1 (b) sqrt(2)+1 (c) sqrt(3)-sqrt(2) (d) sqrt(3)+\ sqrt(2)

Radius of the circle that passes through the origin and touches the parabola y^2=4a x at the point (a ,2a) is (a) 5/(sqrt(2))a (b) 2sqrt(2)a (c) sqrt(5/2)a (d) 3/(sqrt(2))a

The radius of the circle r^(2)-2sqrt(2r) (cos theta + sin theta)-5=0 , is

(r_(2)+r_(3))sqrt((r r_(1))/(r_(2)r_(3)))=

The locus of the mid-points of the chords of the circle of lines radiùs r which subtend an angle pi/4 at any point on the circumference of the circle is a concentric circle with radius equal to (a) (r)/(2) (b) (2r)/(3) (c) (r )/(sqrt(2)) (d) (r )/(sqrt(3))