Two spherical balls lie on the ground touching. If one of the balls has a radius of 7 cm, and the point of contact is 10 cm above the ground, what is the radius of the other ball (in centimeters)? Pick one
A) 30/7	B) 50/3	C) 70/4	D) 80/5	E) 90/8
A straight line will join the two centers and the point of contact, thus making similar triangles.   3/7 = (r-10)/r   3r = 7r - 70   r = 70/4   The answer is 70/4.
<result>C</result>
Two spherical balls lie on the ground touching. If one of the balls has a radius of 7 cm, and the point of contact is 10 cm above the ground, what is the radius of the other ball (in centimeters)?