Question

If |u| = 10, |v| = 8, and the angle formed between them is 60°, then u · v =___ ?

Answer 1

use cosine theorem..

Answer 2

$$
\bf{u\bullet}\bf{v}=|\bf u|\bf|v|\cos\theta\\
$$
Here is the dot product

https://tube.geogebra.org/student/m837511