Given a = 4 and B = 3, when vector A / / vector B, find the product of a and B

Given a = 4 and B = 3, when vector A / / vector B, find the product of a and B

When a / / B, if the direction of vector a and B is the same, then: = 0 °, in this case:
Vector a · vector b = 4 * 3 * cos0 ° = 12,
If the direction of vector a is opposite to that of B, then: = 180 ° and then:
Vector a · vector b = 4 * 3 * cos 180 ° = - 12