As many were opened during the time period. Jk, I don't know. This is a hard one
This is a right triangle (you can confirm by using Pythagorean Theorem: 15² + 36² = 39²)
A = 
A = 
= 15 * 18
= 270
Answer: 270 cm²
The answers are (-3, -4) and (-5, -4).
7^4 * 4^7
hope this helps