Answer:
20%
Step-by-step explanation: The percent of error formula is |(theoretical value-actual value)/actual value|=percent of error. Substitute the values in. |(2.8-3.5)/3.5|=|(-0.7)/3.5|=0.2. The percent equal to 0.2 is 20%.
Answer:

Step-by-step explanation:
The error in rounding a number is half of the unit of measure.
The number was rounded to the nearest 0.1 unit so the error is 1/2×0.1, which equals 0.05.
Now we add 3.7 and 0.05, which equals 3.75 and we also take 3.7 - 0.05, which equals 3.65
So, the error interval is:

Let's take any edge length l. The diagonal has length

. In our case it's