Answer
trapezoid
Work Step by Step
Lets take A(0,0), B(a,0)
then slope of AB= $\frac{0-0}{a-0}$ = 0
Now take D(d,c) and C(b,c)
The slope of DC = $\frac{c-c}{b-d}$ = 0
The slopes of AB and DC are equal
therefore AB is parallel to DC.
Therefore in quadrilateral ABCD, AB||DC,therefore ABCD is a trapezoid.