D. 28
this is because 48 divided by 12 is 4, 4 times 7 is 28.
Answer:


Step-by-step explanation:
The vertices of quadrilateral ABCD are A(1,0) B(5,0) C (7,2) D(3,2).
The slope of side AB is

The slope of side BC is

The slope of side CD is

The slope of AD is



We see that the opposite sides of the quadrilateral ABCD are equal.
Hence the quadrilateral is a parallelogram