Answer:
18th of July
Step-by-step explanation:
Given that each quarter of a moon phase occurs after seven days, hence, if a 1st quarter moon phase appears on the night of July 4th, the approximate date on which a 3rd quarter moon will appear in the night sky on the 18th of July.
This is because, after the first quarter of a moon phase of July 4th, the second quarter of a moon phase will occur on the 11th of July, while the third quarter will occur on the 18th of July.