Moving a point?

Question

Physics

If the added displacements are directed in opposite directions (11b, c), the direction of the resulting one coincides with the direction of the terms whose modulus is greater.
In Figure 11b, the modulus of BC is greater than AC, and the resulting arrow points in the opposite direction. 11c the same.
How it works?

Answer 1

because all the pictures show AB+BC=AC, not BC+AC or AC+AB