Question

please answer fast
please
Area of triangle with vertices (-2, 2), (1,3), (3, 0) using determinant is
​

Answer 1

The determinant formulation says the signed area of a two D triangle is half the volume of the three D parallelpiped with unit depth, i.e. vector sides (-2,2,1),. (1,3,1) and (3,0,1).

So we’re after

| -2 2 1 |

Δ = 1 ∣ 1 3 1 ∣

2 | 3 0 1 |

Area = 1/2 [-2(3−0) – 2(1−3) + 1(9−0)]

= 1/2 [-6 + 4 + 9]

= 1/2 × 7

= 7/2 square units