If it’s a square 381km x 381km then that’s 145161km² (and I’m not aware that there’s any difference between “square kilometres” and “kilometres squared”, is there?)
In writing it’s not clear, but in spoken word you usually stress it like (381 kilometers) *pause* squared, which makes it clear the square applies to both value and unit, (381km)², whereas 381 (kilometers squared) is just 381km²
If it’s a square 381km x 381km then that’s 145161km² (and I’m not aware that there’s any difference between “square kilometres” and “kilometres squared”, is there?)
In writing it’s not clear, but in spoken word you usually stress it like (381 kilometers) *pause* squared, which makes it clear the square applies to both value and unit, (381km)², whereas 381 (kilometers squared) is just 381km²