strength calculations for a step

I can't figure this one out.

I want to add a retractable step that will stick out of the fuselage at
a 40 degree from vertical angle. It sticks out 10" and is made of 3/4"
square, .065 thick, 4130 tube. Assuming no weakness in the support,
will this support a 300lb man (me with all my luggage on my back), and
how can you tell?

--
This is by far the hardest lesson about freedom. It goes against
instinct, and morality, to just sit back and watch people make
mistakes. We want to help them, which means control them and their
decisions, but in doing so we actually hurt them (and ourselves)."