I think 20 Did you try googling it?
Answer:

Step-by-step explanation:
see the attached figure to better understand the problem
we know that
----> by angle addition postulate
substitute the given values

Answer:
rectangular prism
Step-by-step explanation:
The sides fold up into a rectangular shaped box, or a prism. Hope this helps!
Answer:
3√7
Step-by-step explanation:
9²+B²=12²
simplify
81+B²=144
minus the 81
B²= 63
Answer:
10 units
Step-by-step explanation:
use distance formula: d = square root of the difference of the y-values minus the difference of the x-values
d = 
d = 
d = 
d = 10 units