brainly.com/question/5027087Let C, S and H be the diameters of cell, sand and hair
Diameter of a cell:

Diameter of a grain of sand:

Part A:

meters, because it takes 5 movements right of the decimal dot, until there is only one digit to its left.
Part B:
we are comparing

to

,

thus S is 20 times larger than C
Part C

thus,

Part D.

thus 300 nm are written in meters as follows:
The answer to your question is 6.67.
5/6 of the boys brought their lunch.
In order to determine the answer you need to divide 5/9 by 2/3 in which will give you 5/6.
√7 is not a perfect square , so it's irrational
Answer is B. irrational numbers
P.S .
Keep in mind that any of non perfect square is irrational