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

1. Adjust the lengths of the sides of the triangle to make it equilateral. All sides should be of equal length.
2. Add a semicircular cutout at the bottom corner of the triangle. 
3. Ensure that the diameter of the semicircular cutout is approximately 2/3rd of the length of each side of the triangle.