Question

In which of the following quadrant, the ordinate of a point is equal to its abscissa?

• A. $I$
• B. $II$
• C. $III$
• D. $IV$

Answer 1

Answer: (A), (C)

The correct options are
A $I$
C $III$

A point on the cartesian plane is of the form $(x,y)$. If the ordinate of the point is equal to its abscissa, then $x=y$.
This means, if $x$ is positive, then $y$ too is positive. Point = $(+x,+y)$
Similarly, if $x$ is negative, then $y$ too is negative. Point = $(-x,-y)$
Hence, the point lies lies either in the first quadrant or in the third quadrant as can be observed from the graph.