Two circles with radii r1 and r2, r1>r2≥2, touch each other externally. If ′α′ be the angle between direct common tangents, then
Let c1& c2 be the centers and r1& r2 be the radius of two circles. Then
Cases Conditions
p. 1.|r1−r2|< c1c2< r1+r2
q. 2. |r1−r2|=c1c2
r. 3.c1c2< |r1+r2|
s.
4. r1+r2< c1r2
t. 5. r1+r2=c1r2