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anonymous

  • 5 years ago

This is my math problem: I a triangle ABC, angle B is 3 times angle A and angle C is 2degrees less than 6 times angle A. Find the size of the angles. ? Can anyone solve this in equation steps?

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  1. sandra
    • 5 years ago
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    right, so this is a problem where you have three variables (the three angles), and so you'll need three equations to solve it

  2. sandra
    • 5 years ago
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    so let's write down three equations

  3. sandra
    • 5 years ago
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    1. B = 3A

  4. sandra
    • 5 years ago
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    2. C = 6A - 2

  5. sandra
    • 5 years ago
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    so there's one equation that's true for all triangles

  6. sandra
    • 5 years ago
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    3. A+B+C = 180 (the sum of all angles in a triangle is always 180 degrees)

  7. sandra
    • 5 years ago
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    now what you need to do is substitute until you get an equation with all one variable

  8. sandra
    • 5 years ago
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    how about let's try and get all A's

  9. sandra
    • 5 years ago
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    so we know B=3A, and C=6A - 2

  10. sandra
    • 5 years ago
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    so let's substitute both of those into the third equation - A+B+C = 180

  11. sandra
    • 5 years ago
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    so A + (3A) + (6A-2) = 180

  12. sandra
    • 5 years ago
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    10A - 2 = 180

  13. sandra
    • 5 years ago
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    10A = 182

  14. sandra
    • 5 years ago
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    A = 18.2

  15. sandra
    • 5 years ago
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    now that you have the value of A, you need to substitute it back into other equations to get B and C

  16. sandra
    • 5 years ago
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    if you do that, you'll have the answer

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