if my length on paper is 15 cm, what would be the dimension in real life?
The dimension in real life would be 15 cm. If the length on paper is 15 cm, then the actual dimension in real life would also be 15 cm as long as the scale factor is 1:1.
for a rectangle
If your rectangle has a length of 15 cm on paper, and you are looking for the actual dimensions in real life, it will depend on the scale factor used.
For example, if the scale factor is 1:10, then the actual length of the rectangle in real life would be 15 cm x 10 = 150 cm.
If the scale factor is 1:5, then the actual length of the rectangle in real life would be 15 cm x 5 = 75 cm.
The dimensions in real life of the rectangle will depend on the scale factor used to draw the rectangle on paper.