All angles of triangles is equal means that that triangle is equailateral triangle with side of a = 4 in.
The formula for the area of equilateral triangle is,
[tex]A=\frac{\sqrt[]{3}a^2}{4}[/tex]
Substitute 4 for a in the formula to determine the area of the triangle.
[tex]\begin{gathered} A=\frac{\sqrt[]{3}}{4}\cdot(4)^2 \\ =4\sqrt[]{3} \end{gathered}[/tex]
So area of triangle is,
[tex]4\sqrt[]{3}[/tex]
