Assertion: humpback whale's fin | /r/HasProperty | 15 feet long
Facets:
Source sentences:
text: These fins are about 1/3 the length of the body or about 15 feet long in an adult humpback whale.
text: Female humpback whales—which are larger than males—can be up to 60 feet long, and their pectoral fins alone can be 15 feet long.