1. Full Scale:
This is the scale used to represent objects as they are or appear in real life or as it is given on a diagram. It is technically written as a ratio of n:n, where n‘ represents any number. e.g. 1:1.
1 mm drawn on the drawing paper represents the same 1mm on the actual object. If the object is either too small or too large to draw full scale, the designer scales it up or down.

2. Reduction Scale:
This is a scale that is used to reduce the size of objects as they appear.
If the size of the object is larger than the size of the drawing paper, then the size has to be reduced.
It is technically written as 1:n, where n could represent any number. E.g., 1:2, 1:10, 1:100, 1:5,000,000, etc.

3. Enlarged Scale:
This scale is used to enlarge objects to be bigger than their usual size. If the size of the object to be drawn is too small for some details to be seen the the size has to be enlarged.
It is technically written as n:1, where n‘ could represent any number. E.g. 2:1, 10:1, 100:1 100,000:1, etc.

Each side of the object is scaled by a scale factor.
In the figure above the enlarged triangle has a scale factor of 2, each side of the image is 2 times larger than the sides of the original triangle. The length of the sides remains in the same proportion to each other. Each line in the image is parallel to the corresponding line in the object. All angles remain the same in the object and the image.

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