* Convert to the same unit: We need to compare the distances using the same unit. Let's convert James' jump to meters.

* Conversion: There are approximately 3.28 feet in 1 meter. So, James jumped 12 feet / 3.28 feet/meter = 3.66 meters (approximately).

* Compare: Robert jumped 4 meters, and James jumped 3.66 meters.

Answer: Robert jumps further than James.