thanks for that, so would i be right in saying that if plane flying at 124 knots on 130 degrees = |ab| @ 124 knots
wind from 225 degrees = |bc| @ 35 knots
line |ca| = ground speed
and angle abc = 95 degrees?
ive worked it out both by maths and by drawing and this is what i get but the book says angle abc is 85 degrees?