There is a relationship between confidence interval and standard deviation:

Where

is the mean,

is standard deviation, and n is number of data points.
Every confidence interval has associated z value. This can be found online.
We need to find the standard deviation first:

When we do all the calculations we find that:

Now we can find confidence intervals:

We can see that as confidence interval increases so does the error margin. Z values accociated with each confidence intreval also get bigger as confidence interval increases.
Here is the link to the spreadsheet with standard deviation calculation:
https://docs.google.com/spreadsheets/d/1pnsJIrM_lmQKAGRJvduiHzjg9mYvLgpsCqCoGYvR5Us/edit?usp=sharing
Just factor. y = (x-1)(x-1)
Answer:
195 sq cm
Step-by-step explanation:
15 x 15 = 225
----------------------
3(8) + 2(3) = 30
----------------------
225 - 30 = 195 sq cm
Step-by-step explanation:
21:18=7:6
42:36=7:6
63:54=7:6