12 pages
Each side count as a page
21+15=36 36/3=12
Answer:
can you please show more details about the question
-1/4
This will remain its absolute value
Well to find the missing side you're going to need the other two. Take the one side and multiply by itself. Take the other one and multiply by itself. Add those two products. Then root it. Basically find something that multiplys by itself to get that product