The area ( in square units) of the triangle formed by the points A( a,0) O(0,0) B(0,b) is ?

Since A(a,0) lies on the x-axis, the distance of this point from the origin is a, and thus it forms the base of the triangle.

Similarly, B(0,b) lies in the y-axis. So, the distance of this point from the origin is b and it forms the height of the triangle.

We know that the formula for finding the area of a triangle is = 1/2 x base x height sq.units.

Substituting the values for base and height, we find that-

Area of triangle = 1/2 x a b sq.units = ab/2 sq.units.