Respuesta :

Find the area of each triangle then multiply by the number of triangles in each polygon

For example, the first  cpolygon 

area of 1 triangle =  1/2 * h * b =  0.5 * 0.5 * 1.73 =  0.4325
So the area of the polygon = 3 * 0.4325 =  1.2975