There are two circles C of radius 1 and C_r of radius r, which intersect on a plane. At each of the two intersecting points on the circumferences of C and C_r , the tangent to C and that to C_r form an angle of $120 degree$ outside of C and C_r. Fill in the blanks with the answer .....
Can you explain to me the given information above? With the image of the condition it describes if possible. Because English is not my mother language. But i want to be able to understand and solve it.
They are talking about this scenario (which I've drawn with circles of the same radius, but the problem allows the radii to be different). By the symmetry of the circles, the other intersection will also be at $120^\circ$.