The other day, I was looking at two intersecting straight lines. They were drawn from a certain angle so that they looked acute. But if you sort of changed the angle of your view (by turning the paper a bit to the side), it looked like, quite simply, a coordinate plane without a graph. So, since the two lines where perpendicular to each other, does it mean they are right angles? Even if they only look acute?(adsbygoogle = window.adsbygoogle || []).push({});

My sister and I had quite a bit of a quarrel over this...and I wanted an answer that was more substantiated, or rather "standard" so that more people could agree. Okay, so bring it on...

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# Different perspectives

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