I'd say what you would do is:
You can either
1. Add 15 and 18 together and then divide by 2
OR
2. Since there is a 3 number difference between 15 an 18, just add 3 to 18
Since this is a 45-45-90 triangle, n = 9 and m = x
I think you can put bench mark place valie round tenth thousnadth
Multiply equation II by 2 and then add up the equations.
Answer:
A≈113.1
Step-by-step explanation: