Angles: Acute, Right, Obtuse, ReflexDate: 06/06/2001 at 23:12:07 From: vosia Subject: Math angles How can I remember what the names of angles mean? For example, acute angle, right angle. Date: 06/07/2001 at 23:17:19 From: Doctor Peterson Subject: Re: Math angles Hi, Vosia. Here they are: \ | / \ | / \ A |A / A +------- +------- +------- obtuse right acute angle >90 90 <90 degrees We can start with the right angle: it's called that because it "stands upright." Just remember it's an "upright angle." Next, the acute angle. That word comes from a word that means "sharp"; a sharp pencil or a sharp knife will look like this. An acute pain is a sharp pain. Acupuncture uses sharp needles. And, if all else fails, you can remember that an aCUTe angle is one that can CUT you! Finally, we don't use the word "obtuse" so much apart from angles; but it means "dull." If a person isn't very "sharp" (doesn't have an acute intelligence), he may be called "obtuse." If that doesn't stick in your mind, just remember that if it isn't right or acute, it's obtuse. Perhaps I should mention a fourth kind of angle, the reflex angle. This can look like any of the others, but we're measuring it around the back; if what we're measuring is on top, it will look like this: A +------- / / / reflex >180 degrees "Reflex" means "bent back"; it's like an elbow that bent too far, which would probably hurt a lot. I hope this makes the names memorable; if you need any more help, and especially if your problem was not with the names but something else, please write back. - Doctor Peterson, The Math Forum http://mathforum.org/dr.math/ |
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