1) When the larger wheel rotates once, the whole turning length of the belt is 2π×9= 18π decimeter.

The belt drives the small wheel so long that it takes 28.26 decimeters for the small wheel to turn once.

So the wheel has 18π/28.26=2 revolutions.

2) The total length of turning circles at both ends of the runway is 400- 130×2= 140.

That is, the circumference of a circle is140m.

Then the diameter is140/π = 44.6 m.

If you have any questions, just ask.