Answer:
about 77 cm^2
Explanation:
From 3 sides, the area of a triangle is conveniently calculated using Heron's formula:
A = √(s(s -a)(s -b)(s -c))
where s is the semi-perimeter: s = (a+b+c)/2.
For the given values of a, b, c, we have ...
s = (a+b+c)/2 = (18 +11 +14)/2 = 21.5
A = √(21.5·3.5·10.5·7.5) = √5925.9375
A ≈ 76.9801 . . . cm^2
The area is about 77 square centimeters.