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anonymous

  • one year ago

Not 100% sure looking for clarity A source of laser light sends rays AB and AC toward two opposite walls of a hall. The light rays strike the walls at points B and C, as shown below:

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  1. anonymous
    • one year ago
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    What is the distance between the walls? 80 m 180 m 90 m 100 m

  2. anonymous
    • one year ago
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    @freckles

  3. anonymous
    • one year ago
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    @SolomonZelman

  4. anonymous
    • one year ago
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    @Owlcoffee

  5. anonymous
    • one year ago
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    @Vocaloid !!

  6. Vocaloid
    • one year ago
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    alright, let's split the distance between the wall into two pieces, A and B, ok? we're going to solve for A and B using trigonometry |dw:1435783301582:dw|

  7. Vocaloid
    • one year ago
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    |dw:1435783435188:dw|

  8. anonymous
    • one year ago
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    I got 90m

  9. anonymous
    • one year ago
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    ?

  10. Vocaloid
    • one year ago
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    as the final answer, or for A?

  11. anonymous
    • one year ago
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    as for the final answer? what do you think it is? I got 90m

  12. Vocaloid
    • one year ago
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    uh, that's not quite right, can you try solving cos(60) = A/40 for A?

  13. anonymous
    • one year ago
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    i dont belive its B or D is it A then?

  14. Vocaloid
    • one year ago
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    we'll find the answer in a minute, hold on if cos(60) = A/40, then what is A?

  15. anonymous
    • one year ago
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    80m?

  16. Vocaloid
    • one year ago
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    not quite... cos(60) = A/40 what happens when you multiply both sides by 40?

  17. anonymous
    • one year ago
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    180?

  18. Vocaloid
    • one year ago
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    A = 40*cos(60)

  19. Vocaloid
    • one year ago
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    plug that into your calculator and tell me what you get.

  20. anonymous
    • one year ago
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    60 * 40 = 2400

  21. anonymous
    • one year ago
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    sorry im bad at this

  22. Vocaloid
    • one year ago
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    cos(60), not 60

  23. Vocaloid
    • one year ago
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    look for the cos() button

  24. anonymous
    • one year ago
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    i got 100

  25. Vocaloid
    • one year ago
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    use this calculator and type in 40 * cos(60) http://web2.0calc.com/

  26. anonymous
    • one year ago
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    20

  27. Vocaloid
    • one year ago
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    much better, lets move on to the next part... |dw:1435784134047:dw|

  28. Vocaloid
    • one year ago
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    ok, we can use a different trigonometric ratio, tan(45) = opposite/adjacent = 80/B tan(45) = 1, so 1 = 80/B, so B = 80

  29. anonymous
    • one year ago
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    Okay so the answer is A than? I think i understand

  30. Vocaloid
    • one year ago
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    no, please hold on...

  31. Vocaloid
    • one year ago
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    |dw:1435784284536:dw| going back to the original diagram, the distance across the wall is A + B A = 20 B = 80 so what is A + B?

  32. anonymous
    • one year ago
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    100m

  33. Vocaloid
    • one year ago
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    right

  34. anonymous
    • one year ago
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    thank you so much you made my day <3

  35. anonymous
    • 11 months ago
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    Actually, you would subtract A (80) and B (20) to get 60 as your true answer. I just took the test and got that right.

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