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christinaxxx

  • 4 years ago

how do u use trigonometry to determine an angle of an isosceles triangle??

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  1. ash2326
    • 4 years ago
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    Supposedly we are given the sides of isosceles triangle. If we draw a perpendicular from the vertex to the third side (two other sides are equal). It'll bisect the third side. |dw:1331409664200:dw|

  2. ash2326
    • 4 years ago
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    We need to find the two angles x and the third angle y we know \[ \cos \theta= \frac{base}{hypotenuse}\] here \[\cos x= \frac{b/2}{a}\] from this we can find x and y=180-2x

  3. amistre64
    • 4 years ago
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    angles are determined by undoing a ratio

  4. amistre64
    • 4 years ago
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    trig(angle) = ratio angle = arctrig(ratio)

  5. amistre64
    • 4 years ago
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    which angle are you interested in finding?

  6. christinaxxx
    • 4 years ago
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    both of them

  7. amistre64
    • 4 years ago
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    there are 3 angles in a triangle :) I assume you mean the base angles?

  8. christinaxxx
    • 4 years ago
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    yup! sorry bout that

  9. amistre64
    • 4 years ago
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    in order to determine the solution to any triangle we need a few bits of information to deduce the unknowns with

  10. amistre64
    • 4 years ago
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    do you have a particular example we can work on?

  11. christinaxxx
    • 4 years ago
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    unfortunately...no :( its a studyguide for finals and i'm reviewing

  12. amistre64
    • 4 years ago
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    well, there are 2 "laws" that can be used when we have certain information; one is the law of sines and the other is a more adaptable form of the pythag thrm

  13. amistre64
    • 4 years ago
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    law of sines equates angles with the length of the side opposite the angle \[\frac{sin(C)}{c}=\frac{sin(B)}{b}=\frac{sin(C)}{c}\] |dw:1331413584401:dw|

  14. amistre64
    • 4 years ago
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    the law of cosines is the more general form of the pythag thrm: \[c^2=a^2+b^2-2ab\ cos(C)\]

  15. amistre64
    • 4 years ago
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    when the angle C is 90 degrees; that simply reverts the the usual: c^2=a^2+b^2

  16. amistre64
    • 4 years ago
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    the law of cosines is good for determing the length of sides; and the law of sines is easier to implement once you know the ratio of angles and sides

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