The routine area returns the area or surface area of the input object which is a triangle, a sphere, or a regular polyhedron.

The command with(geom3d,area) allows the use of the abbreviated form of this command.

$\mathrm{with}\left(\mathrm{geom3d}\right)\:$

$\mathrm{triangle}\left(\mathrm{ABC}\,\left[\mathrm{point}\left(A\,0\,0\,0\right)\,\mathrm{point}\left(B\,2\,0\,0\right)\,\mathrm{point}\left(C\,1\,3\,0\right)\right]\right)\:$

$\mathrm{area}\left(\mathrm{ABC}\right)$

$3$

$\mathrm{icosahedron}\left(\mathrm{ico}\,\mathrm{point}\left(o\,1\,2\,5\right)\,1\right)$

$\mathrm{ico}$

$\mathrm{area}\left(\mathrm{ico}\right)$

$\frac{4\sqrt{3}\sqrt{5}}{\frac{1}{2}+\frac{\sqrt{5}}{2}}$

$\mathrm{draw}\left(\mathrm{ico}\,\mathrm{style}=\mathrm{patch}\,\mathrm{lightmodel}=\mathrm{light4}\,\mathrm{orientation}=\left[-136\,56\right]\,\mathrm{title}='\mathrm{icosahedron}'\right)$