Answer:
 
 
Step-by-step explanation:

 
        
                    
             
        
        
        
Answer:By definition, perpendicular line are two lines that intersect at right angles. In other words, the angle made by two lines should be 90°. Therefore, the use of distance formula does not help because it only tells you if the sides are equal. It does not tell you about the intercepted angle.
A technique that can help you to know if two straight lines are perpendicular is is you find their slopes. Let's say the slope of line 1 is m1 and the slope of line 2 is m2. If m1*m2 yields a product of -1, then the lines are perpendicular. This is because if m1 is the negative reciprocal of m2, the lines are perpendicular. But if m1=m2, the lines are parallel, meaning they don't intersect at all.
Therefore, the answer is: Find the slopes and show that their product is -1.
hope it help
 
        
             
        
        
        
-- If the 55° angle is one of the two equal angles, then 
the third angle is 70° .
-- If the 55° angle is the third angle, then each of the two 
equal angles is 62.5° .
-- For either of these cases, there are an infinite number 
of possible sets of side-lengths.
The statement in the question does not hold water.