The area (A) of a regular hexagon in terms of its side length s is
... A = (3√3)/2·s²
For a regular hexagon, its side length is equal to the radius of its circumcircle, given here as 10√3 cm. Putting this value in the formula gives
... A = (3√3)/2·(10√3 cm)² = 450√3 cm²
... A ≈ 779.4 cm² . . . . area of the hexagon