We know that
• The ramp is 196 meters long.
,
• The barrel has a circular base, it turns 49 times over the ramp.
Observe the ramp longitude is 49 times greater than the lateral surface of the barrel. Let's divide.

This means the circumference of the base of the barrel is 4 meters long.
The circumference length formula is

Where d is the diameter. Let's replace the circumference and solve for d.

Therefore, the diameter is 1.27 meters long, approximately.