Answer: The required area of the given equilateral triangle is 20.78 ft².
Step-by-step explanation: We are given to find the area of the equilateral triangle shown in the figure.
We know that the area of an equilateral triangle having radius of circumscribed circle equal to r units is given by
![A=(3\sqrt3)/(4)r^2.](https://img.qammunity.org/2019/formulas/mathematics/middle-school/fx9g7l7v9rm76rbc2aew87dal2xamjb9oh.png)
For the given equilateral triangle, we have
r = 4 ft.
Therefore, the area of the given equilateral triangle is
![A=(3\sqrt3)/(4)* 4^2=12\sqrt3=20.78.](https://img.qammunity.org/2019/formulas/mathematics/middle-school/at1ocxijpa297zgvppmwhdwpz830y6i7ey.png)
Thus, the required area of the given equilateral triangle is 20.78 ft².