Question

State True or False:
The lines $x=9$ and $y=9$ are perpendicular to each other.

Answer 1

Given lines are $y=9$ and $x=9$

Let's draw these lines on the graph.

The line $x=9$ is parallel to $y$-axis and ${\perp }^{ar}$ to $x$-axis.

And line $y=9$ is parallel to $x$-axis and ${\perp }^{ar}$ to $y$-axis.

Clearly, from the graph we see that they intersect each other at the point $(9,9)$ and make an angle of ${90}^o$.

Thus, the two given lines are perpendicular to each other.