20)
The sketch of the given data is
By observing the sketch, the longest line is A.
Hence the specimen A is the longest.
21)
In the microscope, the size of the specimen is 0.75cm long.
It is given that the microscope enlarges the actual length 100 times.
[tex]\text{Size =100}\times Actual\text{ length}[/tex]
[tex]\frac{\text{Size }}{100}\text{=}Actual\text{ length}[/tex]
Substitute Size=0.75, we get
[tex]\frac{0.75}{100}=\text{Actual length}[/tex][tex]\text{Actual length=0.0075 cm}[/tex]
Hence the actual length of the specimen is 0.0075cm.
