Rods

Well the green one is 2 cm with the shadow being 3 cm. This means the shadow is 1.5 times bigger than the rod. The red shadow is 10cm making the red one 15cm.
Either that or i can't shadow and i need to use pythagorous but I'm not sure

Not correct, but you don't need Pythagoras. Can be worked out logically.

I don't know much about shadows, 6-4 is 2 so the shadow against the wall is really 2 cm and the red rod is 8 cm?

The red rod is indeed 8 cm.

Idk