Roof area from plan and slope

Converts roof plan area into approximate sloped roof area using the pitch angle.

Calculates roof pitch angle as arctangent of rise divided by run.

Calculates roof slope percent from rise and horizontal run.

Helper calculation of geometric rafter length from run and rise; it is not code-based design.

Calculates stair slope angle from riser height and tread depth.

Helper calculation of net wall area after subtracting openings; it is not code-based design.