The Brainliest Answer!

This Is a Certified Answer

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.
Both laws are same and equivalent.  If you have a triangle, then we can use the triangle law.  If you have a parallelogram, use that law.

In general the parallelogram law is used, because it is easier to understand and apply.

If you have a parallelogram  ABCD,  then vector AB + vector BC = vector AC. AC is the third side of triangle ABC.  This is triangle law.

vector AD + vector AB = vector AC.   
this is parallelogram law.

(but we have vector AD = vector BC..)

2 5 2