The area for 27 is 64cm^2.
For the mean, you add up all the numbers then divide by how many numbers there are. So you would do 45+96+100+39+50 and divide it by 5. So your mean is 66.
Now for 29.
For when n=5 is 8
For when n=8 is 14
For when n=14 is 26
Hope this helps!