That depends on your typesetting ability when drawing. Some are marked with dimensions, and some are not, so if they are not marked, you should be able to calculate the dimensions through mathematical operations. This will not change the overall structure of the chart. Maybe he is testing your mathematical operation ability and giving you a method. That is, you can use a ruler to measure the actual length of the size he marked on the drawing, use the length of the target and the length on the drawing to calculate the scaling ratio (just do division directly), then measure the length without the target, use the calculated ratio to calculate the length of the target, and then make a drawing with CAD. These two methods have their own advantages. The first is to test your math and geometry ability, and the calculation is more accurate. The second is the most basic multiplication and division method, which does not have much mathematical knowledge, but it is not as accurate as the first.