Answer:
249.42 units²
Step-by-step explanation:
Given only the apothem of an n-sided regular polygon, the area can be computed as ...
... A = n·a²·tan(180°/n)
For n=3 and a=4√3, this is ...
... A = 3·(4√3)²·tan(60°)
... A = 3·48·√3 = 144√3 . . . . units²
... A ≈ 249.42 units²
The simplest path from (0, 0, 0) to (1, 1, 1) is a straight line, denoted
, which we can parameterize by the vector-valued function,

for
, which has differential

Then with
, we have



Complete the square in the quadratic term of the integrand:
, then in the integral we substitute
:


Make another substitution of
:

Integrate by parts, taking




So, we have by the fundamental theorem of calculus that


