Answer:
50% 
Step-by-step explanation:
due to the fact that its true/false questions, so that means when you answer you have 2 choices. a 50/50 chance of getting them right or wrong 
 
        
             
        
        
        
Answer:
90°, 270°
Step-by-step explanation:
2r sin(Ф/2) = c
2r sin (Ф/2) = √2r
divide both sides by 2r
sin (Ф/2) = √2r/2r
sin(Ф/2) = √2/2
From the unit circle sin is √2/2 at 45°, and 135°
so Ф/2 = 45
Ф=90°
and Ф/2 = 135
Ф= 270°
 
        
             
        
        
        
Consider the equation

1) First row of the table
Set x=0 and solve as follows:

The answer is y=20 and the pair x-y is (0,20)
2) Second row
Set x=1 and solve, as follows:

The answers are y=10 and (1,10)
3) Third row.
Set y=0 and solve as follows:

The answers are x=2 and (2,0)