Please tell me that post is an April Fool?
You need to understand how the triangle of velocities works, and how the whizz wheel draws it for you. Getting the answer on an App (particularly if it shows that you're wrong) isn't going to help. Get someone to show you (instructor?) or read the instructions.
I know we dont need them when we just follow the gps
, but a route calculated properly using the whizz wheel is a joy - especially when you understand how it works.
ps sorry I'm so grumpy - but I mean what I say