In vector algebra, if you have two vectors, x and y which are not collinear, and x + y is the vector resulting from the two acting together then the magnitude and direction of x+y is given by the diagonal of the parallelogram whose adjacent sides are x and y.
If x and y are collinear then the result still hold if you consider the common line as a totally flattened parallelogram.
yes
No.
no
4
yes
Yes.
No, a parallelogram is not a trapezoid.
parrallelogram
It is a special kind of parallelogram.
A rhombus
180. Degrees
Yes it is a quadrilateral polygon.