9514 1404 393
Answer:
20.78 square units
Explanation:
The area of a regular polygon of radius r and number of sides n is given by ...
A = (n/2)r²sin(360°/n)
For this regular 3-gon of radius 4, the area is ...
A = (3/2)(4²)sin(360°/3) = 24(√3/2) = 12√3 . . . square units
The area is about 20.78 square units.