Area of a Triangle (Leaving Cert Mathematics): Flashcards

$\frac{1}{2}|x_1y_2 - x_2y_1|$

Absolute value

When one vertex is at origin (0,0)

Multiply $x_1$ by $y_2$ and $x_2$ by $y_1$

Find difference between products

To ensure area is always positive

Multiply by $\frac{1}{2}$

Translate triangle so one vertex moves to (0,0)

No

Yes, result will be same

Forgetting to take absolute value

Forgetting to multiply by $\frac{1}{2}$