Five marbles of descending sizes are placed in a conical funnel. Each marble is in contact with the adjacent marble(s). Also, each marble is in contact all around the funnel wall.

If the smallest marble has a radius of 8mm, and the largest marble has a radius of 18mm, what is the radius of the middle marble?

Bonus question, suggested by "Juggler": what's the angle of the funnel walls?

The required radius of the middle marble is 12 mm

Edited on August 4, 2023, 9:10 am

Posted by K Sengupta on 2022-03-20 02:40:18