Because it will make your sentence positive.
Example- My greatest achievement was when i won the 8th grade chess tournament.
my achievement is to become a supermodel :P
50%, one half. (Good luck getting a career in life if you're going to use the internet to cheat on your fourth grade math homework.)
Use estimation when an approximate answer is acceptable.
The prince was the heir to the throne.
The other side of my jacket has a different pattern, which means it is reversible.
"After many years of study he graduated with a Master's Degree in Business Administration." or, with a synonym: "He was master of his domain."-taken from the Seinfeld TV show.
The compromise was found acceptable by both sides.
It is not acceptable to be unable to use acceptable in a sentence.
He came in fourth place.
That person is in third grade
I will GRADE a paper tonight!! :)
That person is in 3rd grade
She and I have been close friends since we were in the fourth grade.
The complaisance of the candidate demonstrated is acceptable.
Yes, using a gerund to begin a sentence is acceptable and can add variety to your writing. Just make sure the gerund phrase is properly structured and fits the context of the sentence.