TriangleMeasurement

TriangleMeasurement[tri, type] gives the specified type of measurement for the triangle tri.

Examples

TriangleMeasurement[Triangle[{{0, 0}, {1, 0}, {0, 1}}], "Area"]

TriangleMeasurement[Triangle[{{0, 0}, {3, 0}, {0, 4}}], "Perimeter"]

Please visit the official Wolfram Language Reference for more details.