Answer:
544,000
Step-by-step explanation:
For this case we have the following data:


So that the figure can be a rectangle, its diagonals must be equal, that is, 
In this way we have:

Clearing x we have:


Thus, x must be equal to 10 so that the figure is a rectangle.
Answer:

Option A
Answer:
Step-by-step explanation:
Order shouldn't make any difference.
3 C 4 = 4!/(3! 1!) = 4
Let's see if that is right.
1 2 3
1 2 4
1 3 4
2 3 4
Any other combination will produce a duplicate if order doesn't matter. For example
2 4 3 is the same thing as 2 3 4