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Math Help - Trigonometry and Surds

  1. #1
    OJW
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    Question Trigonometry and Surds

    Hello there,

    I have a problem solving question which has been frustrating me:

    A triangle has sides of lengths √6, 3√2 and 3√3 units.

    Is the triangle right angled? You must give a reason for your answer.

    Any help would be greatly appreciated, thank you.

    OJW
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  2. #2
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    e^(i*pi)'s Avatar
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    Quote Originally Posted by OJW View Post
    Hello there,

    I have a problem solving question which has been frustrating me:

    A triangle has sides of lengths √6, 3√2 and 3√3 units.

    Is the triangle right angled? You must give a reason for your answer.

    Any help would be greatly appreciated, thank you.

    OJW
    1) Use Pythagoras Theorem - if the sum of the squares of the two shorter sides equals the square of the longest side then it is a right angled triangle. (in other words does a^2+b^2=c^2)

    2) Use the cos rule to find an angle - if it's 90 degrees then it's a right angled triangle \left( \cos(C) = \frac{a^2+b^2-c^2}{2ab}\right)
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  3. #3
    OJW
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    Quote Originally Posted by e^(i*pi) View Post
    1) Use Pythagoras Theorem - if the sum of the squares of the two shorter sides equals the square of the longest side then it is a right angled triangle. (in other words does a^2+b^2=c^2)

    2) Use the cos rule to find an angle - if it's 90 degrees then it's a right angled triangle \left( \cos(C) = \frac{a^2+b^2-c^2}{2ab}\right)
    Thank you very much, that's a perfect explanation!

    OJW
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