Answer:
43.3
Step-by-step explanation:
since it is a regular polygon thus it is a equilateral triangle where all sides are the same and all angles are 60
use formula 1/2 x a x b x sin C where a and b are sides and C is the angle
1/2 x 10 x 10 x sin 60 = 43.30
or method 2 is using Pythagoras theorem by drawing a perpendicular height to length 10km
h = [tex]\sqrt{10^{2} - (10/2)^{2} } = \sqrt{75} \\[/tex]
area of triangle = 1/2 x 10 x [tex]\sqrt{75}[/tex] = 43.30
