PLEASE HELP WITH 8 and 9 :)

Mathematics
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Oct 9th, 2014

8.

Now for first triangle ,

Cos (57 degree) = 21.8/x

x = 21.8 / Cos (57 degree)

x = 21.8 / 0.545

x = 40 cm

Now 

Theta = 90 degree - 57 degree = 33 degree       then

Cos (33 degree) = y / x

y = x * Cos (33 degree)

y = 40 * 0.838

y = 33.52 cm

9.      

Now    92^2 = 54^2 + BC^2

           BC^2 = 92^2 - 54^2

           BC = √92^2 - 54^2

           BC = √8464 - 2916

          BC = √5548

         BC = 74.5

Now for Angle C 

Tan Angle C = 54 / 74.5

Angle C = Tan^-1(54 / 74.5)

Angle C = Tan^-1(0.7248)

Angle C = 35.9 degree

Now    180 degree = 96 degree + 35.9 degree + x

           x = 180 degree - 96 degree - 35.9 degree

           x = 48.1 degree

 Now   Cos (48.1 degree) = CD / CE

           Cos (48.1 degree) = 61 / CE

           CE = 61 / Cos (48.1 degree)

           CE = 61 / 0.668

           CE = 91.3

Hence    CE = EC = 91.3

10.     

Here 47 degree wire is higher, then

Now 

        Tan (47 degree) =  x / 10

              x = 10 * Tan (47 degree)

              x = 10 * 1.072

              x = 10.72 m

The higher wire is 10.72 m high.

Now 

        Tan (37 degree) = x / 10

              x = 10 * Tan (37 degree)

              x = 10 * 0.754

              x = 7.54 m

The bottom wire is 7.54 m high.

Now   10.72 - 7.54 = 3.18 m

Hence    The higher wire is 3.18 m high form bottom wire.

Oct 10th, 2014

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Oct 9th, 2014
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Oct 9th, 2014
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