The Reuleaux triangle is shown in the attached figure
we know that
the area of a Reuleaux triangle is equal to
[tex] A=\frac{1}{2} *(\pi -\sqrt{3} )*r^{2} [/tex]
where
r=18.6/2--------> r=9.3 m
so
[tex] A=\frac{1}{2} *(\pi -\sqrt{3} )*9.3^{2} [/tex]
[tex] A=60.96 [/tex]
therefore
the answer is
61 m²