Let's take this step-by-step:
The mathematical name of this shape is a right trapezoid
⇒ It is a trapezoid since the image shows a quadrilateral that
has two parallel sides and two non-parallel sides. It is a right
trapezoid because it has two rights angles
The cube has 6 faces
⇒ faces are the individual flat surfaces of an object
⇒by looking at a picture of a cube, we see it has 6 sides
⇒ (I attached an image of a cube below)
Hope that helps!