Angle Between Two Planes

In Euclidean space, a Euclidean vector is a geometric object that possesses both a magnitude and a direction. A vector can be pictured as an arrow. Its magnitude is its length, and its direction is the direction that the arrow points to. The magnitude of a vector n₁ is denoted by ||n₁||.

The dot product of two Euclidean vectors n₁ and n₂ is defined by

n₁· n₂ = ||n₁|| ||n₂|| cos α

where α is the angle between n₁ and n₂.