Final answer:
The astrolabe and magnetic compass were significant to Europeans as they allowed for transoceanic voyages. The astrolabe provided directional guidance using constellations, while the magnetic compass enabled navigation in any direction.
Step-by-step explanation:
The astrolabe and magnetic compass were significant to Europeans because they allowed them to navigate transoceanic voyages (D). In the fifteenth century, Europe experienced a navigational revolution by adopting these new non-Western maritime technologies. The astrolabe provided directional guidance by using constellations as a guide, enabling mariners to find their north-south position on the earth's surface. The magnetic compass, which had been used in China since the 1100s, allowed Europeans to confidently navigate in any direction even when out of sight of land.