By using the determinants the area of the triangle with vertices (0, 0), (0, 1) and (1, 0) is :

1 2 $\frac{1}{2}$ $\frac{1}{4}$

$\frac{1}{2}$

The correct answer is Option (3) → $\frac{1}{2}$ so area of $Δ=\frac{1}{2}\begin{vmatrix}0&0&1\\0&1&1\\1&0&1\end{vmatrix}$ $=\frac{1}{2}$ sq. units