Based on the answers provided, here are the corrections needed for the 3D object:

1. Make sure the top of the object is shaped like an isosceles trapezium. This means the non-parallel sides of the trapezium should be of equal length.
2. Ensure that the longer side of the trapezium is the same length as the larger side of the rectangle. This might require adjusting the dimensions of either the trapezium or the rectangle, or both.