Question

Find the area of the triangle OAB , where A is a point which lie on the xaxis and is a distance of 4 units to thr right origin O . B is a point on the y axis and is a distance of 3 units above xaxis alsowrite the cordinates

Answer 1

(refer the picture for diagram)

distance of B from O = 3 units

i.e. OB = 3 units

distance of A from O = 4 units

i.e. OA = 4 units

Now, we know that the coordinate axes are always perpendicular to each other, and OA and OB are sides of ∆AOB along x-axis and y-axis respectively.

This shows that OA is perpendicular to OB

i.e. in ∆AOB, OB acts as a height and OA acts as a base

Hence,

area of ∆AOB

= 1/2 x base x height

= 1/2 x OA x OB

= 1/2 x 4 x 3

= 1/2 x 12

= 6 sq. units

Hence, area of the triangle is 6 sq. units.