Question:

Year 10 maths trigonometry problem help please ,cheers! ?

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A cable car is supported by two wires attached to a horizontal cable.

One of the wires is 5.4m long and makes an angle of 43 degrees and 20 minutes with the horizontal cable. the other wire makes an angle of 31 degrees and 45 minutes with the cable. How far apart along the cable are the wires , to 2 decimal places.

The answer was: 9.92 metres

My problem is i can't form the picture in my head , can someone please help show me the methods of how you got the answer! thanks so much .

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5 ANSWERS


  1. email me & i can send u the pic

    trooper_2002_694@yahoo.com

    43deg 20 min = 43.33 deg

    31 deg 45 min = 31.75 deg

    180 - ( 43.33 + 31.75 ) = 104.92 deg

    5.5 / sin 31.75  = x / sin 104.92

    x = ( 5.4 * sin 104.92 ) / sin 31.75

    x = 9.916 m = 9.92 m

    x is how far apart along the cable are the wires , to 2 decimal places.


  2. you draw an obtuse angled (104 deg 55 min) triangle vertex downward and base horizontal with sides making angles 43 deg 20 min and 31 deg 45 min.

    then length of base = 5.4 cos(43deg20min) + 5.4sin(43deg20min)cot(31deg45min) = 9.92  

  3. Ok, yer makin a triangle here

    Draw a horizontal line, this is the moving cable

    Attached to it, hanging down, are the car attaching cables

    They both meet at the top center of the car, making a triangle with the base being up and it is the horizontal line

    First is the one were you know the angle and hyp, you can solve for both the height of the triangle (used in the next calc) and the portion of the horizontal cable on that angles side

    sine = opposite/hyp

    sine (43'20"") = opposite/5.4

    Opposite = 5.4 * 0.68624

    =3.706

    cos = adjacent /hyp

    cos (43'20"") = horizontal port / 5.4

    .727 * 5.4 = horizontal

    3.928

    Now calc the  other part of the horizontal

    tan = opposite / adjacent

    tan (31'45"") = 3.706 / adjacent

    adjacent = 3.706 / 0.6188

    adj = 5.989

    So, add them together 3.928 and 5.989 and you get

    9.917, this rounds to 9.92 m

  4. draw a diagram. remeber cos sin and tan

  5. If x = length of the second wire,

    x = 5.4sin(43.33°)/sin(31.75°) = 7.04 m

    Distance between the two wires

    = 5.4cos(43.33°) + 7.04cos(31.75°)

    = 3.93 + 5.99

    = 9.92 m.

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