Here is a thought experiment.
Consider a frame S in which an observer is at rest and she looks ahead to find a right angle triangle of sides 3 (x-axis),4(y-axis) and hypotenuse 5. Now consider another frame S’ in which is moving at a speed ’ v ’ moving along x-axis, with respect to frame S, that has another observer.
Will the observer in the frame S’ be able to accurately deduce the Pythagoras theorem or will length contraction along the x-axis lead to some other x-axis length for the triangle?