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'Concrete Wheel' printed from http://nrich.maths.org/
Imagine that you are sitting in a room at ground level, facing a
floor-to-ceiling window which is 20 feet by 20 feet.
A huge concrete wheel, 100 miles in diameter, is rolling down the
street and is about to pass right in front of the window, from left
The centre of the wheel is moving to the right at 100 miles per
What does the view look like, from inside the room, as the wheel
This problem appears in "Mathematical Thinking
and Problem Solving", edited by Alan Schoenfeld and published by