Two spherical balls lie on the ground touching. If one of the balls has a radius of 5 cm, and the point of contact is 7 cm above the ground, what is the radius of the other ball?
Choose one.
A) 10 cm  B) 25/2 cm  C) 35/3 cm  D) 15 cm  E) none of the these
similar triangle properties..   2/r+5 = 5/r-5   giving r = 35/3.   Answer: 35/3 cm
<result>C</result>
Two spherical balls lie on the ground touching. If one of the balls has a radius of 5 cm, and the point of contact is 7 cm above the ground, what is the radius of the other ball?