Question

Calcular a área do triangulo de vértices:
b) A (1, 0, 1) B (4, 2, 1) C ( 1, 2, 0)

c) A (2, 3, -1) B (3, 1, -2) C ( -1, 0, 2)

d) A (-1, 2, -2) B (2, 3, -1) C (0, 1, 1)

Answer 1

Pelo modo mais fácil... Determinante dividido por 2
A)$\left[\begin{array}{ccc}1&0&1\\4&2&1\\1&2&0\end{array}\right] = 8 - 4 = \frac{4}{2} = 2$
B)$\left[\begin{array}{ccc}2&3&-1\\3&1&-2\\-1&0&2\end{array}\right] = 6+4-18-1 = \frac{-9}{2} =|-4,5| = 4,5$
C)$\left[\begin{array}{ccc}-1&2&-2\\2&3&-1\\0&1&1\end{array}\right] =-3-4-4-1 = \frac{-12}{2} =|-6 |= +6$