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SetsunaYuregeshi
 one year ago
How do you find the area of this triangle?
SetsunaYuregeshi
 one year ago
How do you find the area of this triangle?

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SetsunaYuregeshi
 one year ago
Best ResponseYou've already chosen the best response.0dw:1438116778704:dwI need to find the area of this. How do I do that?

SetsunaYuregeshi
 one year ago
Best ResponseYou've already chosen the best response.0dw:1438116845340:dw I forgot the right angle

SetsunaYuregeshi
 one year ago
Best ResponseYou've already chosen the best response.0Really? That's it?

SetsunaYuregeshi
 one year ago
Best ResponseYou've already chosen the best response.0But what about:

SetsunaYuregeshi
 one year ago
Best ResponseYou've already chosen the best response.0dw:1438116970196:dw What about that part? WHen they ask find the area which triangle am i finding it for exactly?

phi
 one year ago
Best ResponseYou've already chosen the best response.2You found the area of the triangle. we can prove it

ChillOut
 one year ago
Best ResponseYou've already chosen the best response.0You're finding the are for the full lines one.

SetsunaYuregeshi
 one year ago
Best ResponseYou've already chosen the best response.0I found the area of which triangle?

ChillOut
 one year ago
Best ResponseYou've already chosen the best response.0dw:1438117079817:dw

SetsunaYuregeshi
 one year ago
Best ResponseYou've already chosen the best response.0Ooh, so the dw:1438117132170:dw is giving me the height for the triangle?

SetsunaYuregeshi
 one year ago
Best ResponseYou've already chosen the best response.0Ooh, Brainfart!

SetsunaYuregeshi
 one year ago
Best ResponseYou've already chosen the best response.0Since I am taking geometry during summerschool I expected it to be some complicated formula. At first I ruled out that it could be that...

ChillOut
 one year ago
Best ResponseYou've already chosen the best response.0There are other formulas involving angles and stuff. But leave that for later :)

phi
 one year ago
Best ResponseYou've already chosen the best response.2here is a proof. We assume we know the area of a rectangle is width * height dw:1438117298679:dw

SetsunaYuregeshi
 one year ago
Best ResponseYou've already chosen the best response.0So if I answer using 1/2BxH on a graded assessment it will be correct?

phi
 one year ago
Best ResponseYou've already chosen the best response.2now put in a diagonal. the two triangles are congruent, so the area of each is 1/2 of the rectangle'sdw:1438117369207:dw

SetsunaYuregeshi
 one year ago
Best ResponseYou've already chosen the best response.0So if I answer using 1/2BxH on a graded assessment it will be correct?

SetsunaYuregeshi
 one year ago
Best ResponseYou've already chosen the best response.0They're not expecting a different method?

phi
 one year ago
Best ResponseYou've already chosen the best response.2now make an obtuse triangle dw:1438117452871:dw

SetsunaYuregeshi
 one year ago
Best ResponseYou've already chosen the best response.0@phi Ooh, I see. That makes sense...

SetsunaYuregeshi
 one year ago
Best ResponseYou've already chosen the best response.0ooh. C is the height of dw:1438117583062:dw

phi
 one year ago
Best ResponseYou've already chosen the best response.2if we subtract of the small triangle on the left we are left with the obtuse triangle that is \[ \frac{1}{2} (a+b)\cdot c  \frac{1}{2} b c \\\frac{1}{2} ac + \frac{1}{2} bc  \frac{1}{2} bc \\ =\frac{1}{2} ac \]

phi
 one year ago
Best ResponseYou've already chosen the best response.2hopefully you can follow the logic

SetsunaYuregeshi
 one year ago
Best ResponseYou've already chosen the best response.0I can, so you just proved 1/2BxH right?

phi
 one year ago
Best ResponseYou've already chosen the best response.2yes, that the formula works for obtuse triangles.

SetsunaYuregeshi
 one year ago
Best ResponseYou've already chosen the best response.0Ok thanks. Can I ask another quick question?

SetsunaYuregeshi
 one year ago
Best ResponseYou've already chosen the best response.0How do you find the area of a kite?

phi
 one year ago
Best ResponseYou've already chosen the best response.21/2 the product of the diagonals http://www.mathopenref.com/kitearea.html

SetsunaYuregeshi
 one year ago
Best ResponseYou've already chosen the best response.0Would the diagonals be these? dw:1438117923899:dw

phi
 one year ago
Best ResponseYou've already chosen the best response.2the "crossbars" dw:1438118022805:dw

SetsunaYuregeshi
 one year ago
Best ResponseYou've already chosen the best response.0Ooh, ok sorry but: dw:1438118151545:dw It would be 1+1 x 2 + 3/2 right? @phi

SetsunaYuregeshi
 one year ago
Best ResponseYou've already chosen the best response.0OOps I mean 1+2 x 3+3/2

phi
 one year ago
Best ResponseYou've already chosen the best response.2it would be except that would not be a kite (the diagonals of a kite bisect each other) see http://www.coolmath.com/reference/kites

phi
 one year ago
Best ResponseYou've already chosen the best response.2correction: the longer diagonal bisects the shorter diagonal

SetsunaYuregeshi
 one year ago
Best ResponseYou've already chosen the best response.0Ooh, so what i said was right? I have a problem asking for the area where they give me the length of half of both lines.

SetsunaYuregeshi
 one year ago
Best ResponseYou've already chosen the best response.0Like they give me this...

SetsunaYuregeshi
 one year ago
Best ResponseYou've already chosen the best response.0dw:1438118486114:dw

SetsunaYuregeshi
 one year ago
Best ResponseYou've already chosen the best response.0I just add the 2's and 1's and use the 1/2bxh formula right?

SetsunaYuregeshi
 one year ago
Best ResponseYou've already chosen the best response.0Ooh ok. Thanks.

phi
 one year ago
Best ResponseYou've already chosen the best response.21/2 d1 * d2 (though you can think of the diagonals as the width and height)

SetsunaYuregeshi
 one year ago
Best ResponseYou've already chosen the best response.0Ooh, thank you so much!!!!!!!!!!!!!!
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