Answer:
the first one
Step-by-step explanation:
the two planes intersect at line YZ, where they meet
tip: planes intersects at a line, just like how lines intersect at a point
hope this helps :)
No, because it has a measure under 90 degrees
Answer:
24.
Step-by-step explanation:
We can use the factorial function to find the number of unique arrangements in a word.
There are 4 unique characters in 'OPAL'. As such, 4! = 24.
In the case that there were repeating characters, such as 'OPALA', then we would divide by the factorial of the number of repeating letters. That looks something like this:

Hope this helped.
The answers to your question would be A. Housing B. medical expenses C. Groceries