The confidence interval for the population mean at a

confidence level is

. Here

is the sample mean,

is the critical value such that

, and

, where in turn

is the assumed population standard deviation and

is the sample size.
First find the critical value. By the empirical rule, you might already know that about 95% of a normal distribution lies within two standard deviations of the mean, and that about 99.7% lies within three standard deviations, so you can expect

to lie somewhere between 2 and 3. To be more precise, you can consult a z-score table to find that

.
Plug in everything you know and you find that the 98% confidence interval is
Solve for y. Use 2 as your y-intercept. Graph your slope/line. Since the sign is less than or equal to your line is solid. Then you need to shade.
Answer:
1) The answer is in decimal since 82.8 is not a square number and does not have a proper square root. And the nearest square number to it is 81 whose root is 9 and the upcoming square number is 100 whose root is 10. So the root of 82.8 will be decimal and between 9 and 10.
2) a^2 + b^2 = c^2
14^2 + 10^2 = c^2
196 + 100 = c^2
296=c^2
root of 296 is 17.2
So, x=17.2
Here also the answer is in decimal since it is not a square number. The nearest square number to 296 is 289 whose square root is 17 and the next square number after 296 is 324 whose root is 18. So the square root of 296 will be in between 17 and 18.