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Working with compound angles is never easy. And the angle dimensions in the drawing have parenthesis around them indicating that they are for reference only (with the true angles probably rounded off to the nearest degree)
Instead of the angles, may I suggest you work with Points. The front view provides all the lengths you need to create points in each sharp corner of the tube. Make a plane passing through 3 of the points, and use the 4th point to verify the plane passes through it also. Ignore the round corners (fillets). Cut the tube with the plane. Then add the fillets.
PS: could you attach a picture of the entire drawing, please.