Generally, though not always, we run the flooring in the long direction of the majority of the rooms in a house. The idea behind it is old school...the floor used to be nailed into the joist below and joists generally run perpendicular to the ridge...same as the rafters. Not necessary now, with all the new technologies for flooring....but something that ingrained stays with you.

Hope the pictures will help.

We installed wood flooring in a similar L shaped large room, but also continued the flooring down the hallway. We ran the planks across the narrow width of the room and continued it in the same direction in the kitchen and the hallway, resulting in the flooring running down the length of the hallway.

BUT, we installed one run in the long direction of the living/dining room, perpendicular to the rest of the flooring, to visually cue the separation of the living/dining area from the kitchen and from the hallway. The planks are 5" wide, so a width of one plank was sufficient to do the trick. I should include a photo, but it's too dark to take a decent image now.

Thank you

The hardwood has to be laid perpendicular to your floor joists, that's the answer and as far as I know you have no option in the matter.