when two bubbles cling together in midair their common surface is part of sphere whose center D lies on the line passing through the centers of the bubbles. Also angles ACB and ACD each have measure 60 degrees.

A) show that the radius r of the common face is given by:

r= ab/a-b hint: use the law of sines together with the fact that an angle 0 and its

supplement 180 degrees - 0 have the same sine

B) find the radius of the common face if the radii of the bubbles are 4 cm and 3 cm

C) what shape does the common face take if the two bubbles have an equal radii?

.C

. . .

. . .

a . . . r

. . b .

. . .

. . .

B ---------------------------------D

A