As shown in the figure, three circles which have the same radius r,have centres at `(0,0);(1,1) and (2,1)`. If they have a common tangentline, as shown then, their radius 'r' is -

As shown in the figure,three circles which have the same radius r,have centres at (0,0);(1,1) and (2,1). If they have a common tangentline,as shown then,their radius ' Gamma' is -

If two circles of the same radius r and centres at (-1,2) and (3,6) respectively cut orthogonally,then the value of r is

Find an equation of the circle with centre at (0,0) and radius r.

As shown in the figure,the five circles are tangent to one another consecutively and to the lines L_(1) and L_(2). If the radius of the largest circle is 18 and that of smallest is 8. If radius of middle circle is r, then find the value of r/2

A circle centered at P with radius 4cm and another circle centered at Q with radius 16cm toucheach other externally.A third circle with centre Ris drawn to touch the first two circles and oneof their common tangents as shown in the figure.Then,the radius of the circle with centre R is:

In the circuit shown in figure, the emfs of batteries are E_1 , and E_2 which have internal resistances R_1 , and R_2 . At what value of the resistance R will the thermal power generated in it be the highest? What it is?

In the figure, when the outer circles all have radii 'r', then the radius of the inner circle will be

Two circles of radius r_(1) and r_(2) touches externally at point A have a common tangent PQ. Then find the value of PQ^(2) .

There are 4 circles on the figure.Two of them have radius 2 and the smallest one has radius 1.If the area of the dashed part is equal to the area of the filled part then find the radius of the largest circle.r