<span>if point A( 2,2) is reflected across the line Y then the new position A' is (-2,2) and the distance AY = distance A'Y
if A is reflected across line R it is now at point B and the distance AR = distance BR
lets say the point A(2,2) was perpendicular to the line R at the point (1, 4) then when reflected the point A now at location B will have coordinates</span><span>when flipped over a line of reflection the lengths are still the same
the point to the line of reflection is the same length as the line of reflection to the reflected position
the distance from the original point to the reflected point is twice the distance from the original point to the line of reflection
cannot see your polygon.
here is an example