The true statements among the ones provided are:
A - Scale drawings are used because they are easier to work with than an actual object, such as a building, vehicle or piece of furniture.
C - Scale drawings should have the same proportions as the actual object.
The statements B and D are not true:
B is false because scale drawings do not have the same size and dimensions as the actual object; they are a scaled version, often smaller or larger.
D is also false because scale drawings can be at various scales (e.g., half size, quarter size, etc.), not limited to just being half the size of the actual object.