We cannot calculate the confidence interval without the sample size. However, for the second question, the sample size needed would be 49.
The formula we use is

To find the z-score:
Convert 98% to a decimal: 0.98
Subtract from 1: 1-0.98 = 0.02
Divide by 2: 0.02/2 = 0.01
Subtract from 1: 1-0.01 = 0.99
Using a z-table (http://www.z-table.com) we see that this value is closest to a z-score of 2.33.
Using the z-score, our standard deviation (9) and our margin of error (3), we have:
7 multiply by three u get 21 then add it to the number 28 add u get the answer 49
Answer: To find area of a rectangle, multiply its base (length) by its height (width). Plug in the base, 7 meters, and the height, 8 meters. So the area of Rectangle DFBE is 56 square meters.
88m
HOPE THIS HELPS
If 3+4 = 7 and 6+7 = 7 leads to 3+4 = 6+1, then you are using the transitive property. In general the property says that if a = b and b = c, then a = c.