I have a really basic trig question that I need help with as shown in the diagram below! I'd love to be able to have a go at it as I know I should in these forums but I really can't attempt to do it at all which is a bit embarrassing.
The angle I need is the red highlighted one, or the opposite one.
I hope you can view the photo easily enough!? Any queries please post on here.
Thanks for your help,