Respuesta :

Goalinetsky
Area of a Triangle = [tex] \frac{bh}{2} [/tex]

1: A = [tex] \frac{12x18}{2} [/tex] = 108cm²

2: A = 10·10 + 2([tex] \frac{20x10}{2} [/tex]) = 100 + 200 = 300mm²

3: A = [tex] \frac{1.4x2.1}{2} [/tex] = 1.47m²