Triangle rule of vector addition How to derive the triangle rule of vector addition? Isn't the sum of two sides of a triangle greater than the third side? Why is vector addition OK? Even if vector addition is pseudo mechanics, isn't that a bit misleading

Triangle rule of vector addition How to derive the triangle rule of vector addition? Isn't the sum of two sides of a triangle greater than the third side? Why is vector addition OK? Even if vector addition is pseudo mechanics, isn't that a bit misleading

In fact, it is based on the parallelogram rule to the triangle rule
The parallelogram is divided into two triangles. Because it is a parallelogram, some vectors are equal. It can be deduced that the sum of the vectors of the same starting point on the two adjacent sides is the diagonal of the same starting point. Then replace one side and translate it into a triangle