One way to check them is with graph paper, pencil and ruler, and count the squares. In the first one below, by counting the little squares on the graph paper, you see that AD=25,CD=10,DB=4. And if you put the corner of a sheet of paper at C, you will see that it is a right angle of 90°.It appears that you have done good work, and neatly too, using the notation of this site. Edwin