Because chine has recently started industrializing and the usa uses them for cheeper labor and industry
You must measure the angle with a measurement tool and then write down the angles on paper and do the equation yourself and see what you get if it doesn’t match with one person there wrong if it does match and they solved it the way you did that’s the person that did it right.
Hope this helps:D
I think it the Boston tea party. But if iam wrong Iam so sorry look it up on google that may help