# If #A = <1 ,6 ,9 >#, #B = <-9 ,-6 ,7 ># and #C=A-B#, what is the angle between A and C?

##### 1 Answer

Mar 12, 2017

The angle is

#### Explanation:

Let's start by calculating

The angle between

Where

The dot product is

The modulus of

The modulus of

So,