ayuda porfavor resuelban la formula de heron

[tex]s = \frac{3 + 3 + 3}{2} = 4.5[/tex]
[tex] area = \sqrt{4.5(1.5)(1.5)(15)} [/tex]
[tex]area = \sqrt{15.1875} = 3.897 {cm}^{2} [/tex]