Given that the distance between two lines in the measurement instrument is 0.01m, the maximum error should be 0.01m/2 = 0.005 m.
If you do a good work, the real measure is 1.20m +/- 0.005m, this is between 1.195 and 1.205.
The answer is to be 1.035 multiple by 10. 10
It should be 3.25
S is half the perimeter, so .5*(7+5+10)=11
Plug in 11 and you get A=sqrt(264)
A also is half base times height
sqrt(264)=.5*10*h
h=sqrt(264)/5
h=3.25
