Based on the answers provided, the following corrections need to be made to the 3D object:

1. Modify the cutout at the top of the cylindrical object to resemble a small isosceles trapezium. This means the cutout should have two parallel sides and two non-parallel sides of equal length.

2. Ensure that the trapezoidal cutout is similar to a sector of the circle. This means the cutout should curve along the circumference of the cylinder, rather than being a straight, vertical plane.