Answer:
From Post Office to Store is 7.8 miles
Henry would walk 2.2 h
Explanation:
From Post Office (P) to Library (L) is 6 miles, from Store (S) to Library (L) is 5 miles. And angle SLP is right angle (m∠SLP=90°).
So, from Pythagorean theorem:
If Henry walks 3.6 mph then: