What does displacement describe?

A vector which implies that an object has been moved or has changed its position is called displacement. Displacement is usually associated with length and direction of an imaginary straight point. It is the shortest distance from the initial point to the final point of final position (P). Displacement can also be described as the length between the final and initial point on the shortest path. It means an overall change in direction  of the object or point of a body.

Distance^2= yellow line ^2 (see picture) = 30^2 + 49^2so distance = squareroot of (300^2 +49^2)i dont know if this is how to solve it, but i cnt think of another way