This revision note covers several applications of the scalar product for vectors – namely, how you can use the scalar product to:

• find the angle between vectors or lines
• test whether vectors or lines are perpendicular
• find the closest distance from a point to a line

How do I find the angle between two vectors?

How do I find the angle between two lines?

• To find the angle between two lines, find the angle between their?direction vectorsHow do I tell if vectors or lines are perpendicular?How do I find the shortest distance from a point to a line?