Answer:
C) Subtraction property of equality.
Step-by-step explanation:
Given that, two lines  and
 and  intersect to make pairs of vertical angles:
 intersect to make pairs of vertical angles:
 and
 and  .
.
Kindly refer to the attached image for details of the given angles and lines.
Proof that  :
 :

Here, subtraction property of equality is used in the last step shown in the above.
As per the <em>Subtraction property </em>of equality, when some value is subtracted from both the sides of the equality, equality remains the same.
 
        
             
        
        
        
I'll tell you how to find the answers and just use the give angle measure to solve.
9) angle 11 = angle 14
10) angle 9 + angle 15 = 180
11) angle 10 = angle 3
12) angle 7 = angle 14
        
             
        
        
        
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