Show that the given points form a parallelogram:
 
\(A(3.5,2.5)\), \(B(12,-6)\), \(C(3.5,-3.5)\) and \(D(-5,5)\)
 
Answer:
 
The slope of \(AB =\)
 
The slope of \(CD =\)
 
The slope of \(AD =\) ii
 
The slope of \(BC =\) ii
 
The slopes of \(AB\) and \(CD\) are , so the lines are .
 
Similarly, the slopes of \(BC\) and \(AD\) are , so the lines are .
 
Therefore, \(ABCD\) is a parallelogram.
 
Hence, verified.