The area (in sq. units) of the triangle whose vertices are (0, 0), (a, 0), (0, b), is equal to

$\frac{1}{2}|ab|$

The correct answer is Option (3) → $\frac{1}{2}|ab|$

Vertices: $(0,0),\ (a,0),\ (0,b)$

Area of triangle $=\frac{1}{2}\left|x_1(y_2-y_3)+x_2(y_3-y_1)+x_3(y_1-y_2)\right|$

$=\frac{1}{2}\left|0(0-b)+a(b-0)+0(0-0)\right|$

$=\frac{1}{2}|ab|$