Answer:
[tex]25\sqrt{3}=43.3\ \mathrm{units}[/tex]
Step-by-step explanation:
Area of a triangle = [tex]\frac{1}{2}ab\textrm{sin}(\theta)[/tex] where [tex]a[/tex] and [tex]b[/tex] are the sides of the triangle and [tex]\theta[/tex] is the angle between those two sides.
The side length are 10, and since its an equilateral triangle, the angle is 60 degrees. Thus, the area becomes [tex]\frac{1}{2}(10)(10)\textrm{sin}(60)=25\sqrt{3}=43.3\ \mathrm{units}[/tex]