In the drawing with scale of 100:1, the length of the part is 4cm, and the actual length of the part is calculated

In the drawing with scale of 100:1, the length of the part is 4cm, and the actual length of the part is calculated

This part is too small, isn't it
100/1=4/x
x=0.04cm

A building drawing with a scale of 1:100 is measured to be 60cm in length and 15cm in width. How many square decimeters is the actual area of the building?

The actual length is 60cm * 100 = 6000cm = 60m, and the width is 15cm * 100 = 1500cm = 15m
Actual area: l × w = 60m × 15m = 900m2

On a drawing with a scale of 1:4, the length of a part measured is 5mm. What is the actual length of the part in cm?
If this part is drawn on another drawing with a length of 8 cm, what is the scale on this drawing

Actual length = 4 × 5 = 20 mm = 2 cm;
Scale = 8:2 = 4:1 = 1:0.25;
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