How to determine if a point is inside a rectangle?

Q:
what if the rectangle is rotated?

Given 4 points of the rectangle.
 and a target point.

A:
1:  for each parrallel lines of the rectangle, we apply the point to these lines, and see their signs.     if + and - , then within range.  
similarly for another pair.

2:  ( From leetcode)
we can utilize dot product. The trick is to use dot product to find the projected line from point P onto the rectangle sides, and if its length is shorter than the sides, then the point must be inside the rectangle.