Answer: Option A. 65 m^2
Solution:
Sides: a=10 m, b=14 m, c=20 m
Area: A=?
A=sqrt [p(p-a)(p-b)(p-c) ]
Semi-perimeter: p=(a+b+c)/2
p=(10 m+14 m+20 m)/2
p=(44 m)/2
p=22 m
A=sqrt [ (22 m)(22 m-10 m)(22 m-14 m)(22 m-20 m)]
A=sqrt [ (22 m)(12 m)(8 m)(2 m) ]
A=sqrt [ 4,224 m^4 ]
A=64.99230723 m^2
A=65 m^2