Answer:
=14.69km²
Explanation:
We can use the Hero's formula to calculate the area
A= √(s(s-a)(s-b)(s-c))
s is obtained by adding the lengths of the three sides of the triangle and then dividing by 2, a, b and c are the ides of the triangle.
S=(5+6+7)/2
=9
A=√(9(9-6)(9-5)(9-7))
=√(9×3×4×2)
=√216
=14.69km²