Answer: False
Nothing is 100% certain no matter how sure it seems. This is especially true with statistics. There's always going to be some amount of error. The goal is to minimize the error as much as possible in the best cost-effective manner.
you just have to move the decimal point 9 places to the right thats an easy trick to remember 1849900000
Angle ABC=DEF then
Side AB=DF
Side BC=EF
and Side CA=FD
So if side ac=DF
side DF=6cm.