Answer:
39. The students found different measurements for the length of the same side of textbook because they might not have used the same length of paper clips i.e. the length of their paper clips may vary which led to the variation in the length of the textbook.
40. A long graduated plastic ruler is the tool the students could have used to to accurately measure the length of the textbook in centimeters.
Explanation:
Since the students got varying measurements, it is then clear that the length of the paper clips they used were not of the same length.
In fact, the paper clips of the student that had his measurement to be 6 paper clips long will be longer in length than the student whose measurement was 10 paper clips long.
When measuring length of objects in centimeter, the best tool to use for accurate measurement is the graduated ruler. This tool has the centimeter marks graduated on it. This will give the length of the textbook.
