Open Middle: Same-Side Interior or Exterior Angles
Your task:
![Your task:](https://stage.geogebra.org/resource/qqezx6vw/Y0fPXGaVoGlgLhlH/material-qqezx6vw.png)
Without repeating digits, change the input boxes on the left try to make lines a and b parallel. You can move the LARGE POINTS if you wish! The picture on the right IS drawn to scale.
Explain how you know your setup causes lines a and b to be parallel. What exactly justifies this?