The coordinates a(0, 0), b(0, 4), c(3, 4) and d(3, 0) are graphed and connected together. what 3-dimensional shape will be created when this shape is rotated about the y-axis?

You just have reflect all the above points i.e A(0,0) , B(0,4) , C(3,4) and D(3,0)
in y-axis and then it would be A'(0,0) ,B'(0,4), C'(-3,4) and D'(-3,0) plot these points on graph and you get your answer.

What is the diagram u didn't post that