Answer:
13170
Explanation:
We could just use heron's formula
S=(a+b+c)/2=(155+175+260)/2=295
area=sqrt(S(S-a)(S-b)(S-c))
area=sqrt(295(140)(120)(35))
area=sqrt(173460000)
area=13170 is closest whole number
you could check my work for little errors before you enter anything in if you want :p