Answer: Yes, ABCD is isosceles trapezoid.
Explanation:
Since, If in a trapezoid two opposite nonparallel sides are equal then it is called isosceles trapezoid.
In trapezoid ABCD sides are AB, BC, CD and DA.
According to the question, A≡(2,4) B≡(5,4) C≡(7,1) and D≡(0,1)
After making the diagram of ABCD, we found that DA and BC are nonparallel sides.
And, by the distance formula

⇒
=

⇒
unit.
Similarly,

⇒
unit.
Thus, In trapezoid ABCD, two non parallel sides BC and DA are equal.
Therefore, trapezoid ABCD is a isosceles trapezoid.