When two bubbles cling together in midair, their common surface

Question

is part of a sphere whose center D lies on the line passing through
the centers of the bubbles. Also, the angles ACB and ACD both
have measure 60o
(see the figure).
(a) Show that the radius r of the common face is given by
ab
r
a b
=
−
(

Answer 1

5+5=10