The Dot Product
I define the dot product between two vectors, and show how to calculate this. I then show how the dot product can be used to find the angle between two vectors. I also discuss how the size of the angle affects the dot product. I finally define the projection of a vector onto another vector.
The following resources can be used to further understand this topic:
Video: The Dot Product
Video: Angle Between Vectors
Video: Vector Projection
Online Activity: The Dot Product (Desmos)