Bassenthwaite Lake, just under 6 km (4 miles) in length, lies to the northwest of Keswick.
Bassenthwaite Lake is only 5 km long.
mnli hypothesis: Bassenthwaite Lake is only 5 km long. premise: Bassenthwaite Lake, just under 6 km (4 miles) in length, lies to the northwest of Keswick.