An angle is denoted by the angle symbol ∠ and the three letters representing the name of the angle.
An angle is denoted by the angle symbol ∠ which is then being followed by three letters that will represent the points that form an angle. 
Lets say for example, the expression ∠ABC will mean that “the angle is formed by the points A, B and C” 
where the vertex of the angle is at the point B as it is in the middle.
Angles can also be of different types like:
An Acute Angle which means an angle is less than 90 degrees. 
A Right Angle which means an angle which is exactly 90 degrees. 
An Obtuse Angle which is an angle more than 90 degrees and less than 180 degrees. 
A Straight Angle which is an angle that is exactly 180 degrees. 
And a Reflex Angle which is an angle greater than 180 degrees and less than 360 degrees.
Therefore, an angle is denoted by the angle symbol ∠ and the three letters representing the name of the angle.
Learn more about angles here:
brainly.com/question/25716982
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The surface (call it  ) is a triangle with vertices at the points
) is a triangle with vertices at the points



Parameterize  by
 by

with  and
 and  . Take the normal vector to
. Take the normal vector to  to be
 to be

Then the flux of  across
 across  is
 is



 
        
             
        
        
        
Im guessing this is a rectangle? If so it would be
16+16+25+25
32+50
82 is the perimeter
        
                    
             
        
        
        
Your answer would be R=-5x-4+y
        
             
        
        
        
I believe the answer is 2