## Quick Reference

(in the plane)

The distance from the point *P* to the line *l* is the shortest distance between *P* and a point on *l*. It is equal to |*PN*|, where *N* is the point on *l* such that the line *PN* is perpendicular to *l*. If *P* has coordinates (*x*_{1}, *y*_{1}) and *l* has equation *ax*+*by*+*c*=0, then the distance from *P* to *l* is equal to

where |*ax*_{1}+*by*_{1}+*c*| is the absolute value of *ax*_{1}+*by*_{1}+*c.*

*Subjects:*
Mathematics.

## Related content in Oxford Index

##### Reference entries

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.