Question

When $\overleftrightarrow{PQ}$ intersects $\overleftrightarrow{AB}$ at an angle of ${90}^{\circ }$. Then $\overleftrightarrow{AB}$ is ___ to $\overleftrightarrow{PQ}.$

Answer 1

Two lines intersecting each other, in this case $\overleftrightarrow{AB}$ and $\overleftrightarrow{PQ}$ to form a right angle i.e. ${90}^{\circ }$.
Then, we can say than $\overleftrightarrow{AB}$ is perpendicular to $\overleftrightarrow{PQ}$.