Using the geometer's sketchpad version 4, Tour #6. Building a Kaleidoscope?

Question

First your supposed to open previous sketch from tour 5, then drag one of the endpoints of the V until it reaches close to 45 degrees I've done all of that it's the next step that confuses me. You have to select "your desired givens" what are givens???

Answer 1

"Givens" refers to what you know.  What you have learned from Tour #5.