## Claire4christ 3 years ago I need help with question. Im gonna download question.

1. Claire4christ

2. Claire4christ

3. Algebraic!

who opens .docx anymore?

4. Claire4christ

you can open do docx

5. Decart

you need to use trigonometric functions

6. Claire4christ

i got cos 50=x/90 right

7. Claire4christ

so i got 57.9

8. Claire4christ

The cosine of a 50° angle is 57.9 right

9. Decart

which part the first blank is asking which function to use to find the height

10. Claire4christ

part 1 i think its cosine

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if yo are using cos(50)=x/90

12. Claire4christ

yes that's what i did

13. Claire4christ

and i got 57.9

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then the next part is asking for the reverse how do you find the cosine function with the two sides

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57.8

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then input the cosine of 50 in your calculator for the next blank

17. Claire4christ

its asking this this represents the value created when length _____ is divided by ______ feet.

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the angle is the value when you divide the sides accordingly

Cos 50 degrees is 0.6428

20. Claire4christ

The cosine of a 50° angle is 57.9 is this right for the second part

21. Decart

all the trig functions are is a relationship between the lengths of sides if you divide two known sides and take that data it represents and angle.

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so like radar has said the cosine of 50 is .6428 so the sides divided are also .6428

23. Decart

57.8 is the height of the tower because you multiplied the hypotenuse by the cosine to find x

24. Claire4christ

so it will be .6428x.6428

Cos is the adjacent side divided by the hypotenusel.

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what happens if you divide the side x by the side of 90

27. Claire4christ

adjacemt side is x right and hypotenusel is 90

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so 57.8 divided by 90

29. Claire4christ

that's what i got

$\cos 50^{0}=x/90 ft$

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you get .6422

32. Claire4christ

i got 57.9

33. Decart

roughly the same as the cosine for 50 degrees

$x=.6428 \times90$

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|dw:1349577896978:dw|

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that is what we have so far

37. Claire4christ

so it would be 57.9

38. Claire4christ

so x side is 57.9

Yes

when angle was 50 degrees

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$\cos(50^{0})=\frac{ adjacent }{ hypotenuse}$

42. Claire4christ

The cosine of a 50° angle is .6422 right

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the first question only wanted to know that you would use the cosine function to find x

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the next blank wants you to input the cosine of 50 which you have .6422

45. Claire4christ

its .6428

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yes if you type in cos50 in your calculator that is what you get

47. Claire4christ

this represents the value created when length ____ is divided by ____ feet.

48. Claire4christ

49. Decart

if you look at the funtion you know that it is x divided by the 90 feet if you divide the value you got for x by 90 it is about the same as cos 50

50. Claire4christ

when length is 50 is divided by x feet right

51. Decart

no 50 is the angle you want the height of the tower divided by the lenght of the decline which is 90

52. Claire4christ

when length is 90 divided by x feet

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|dw:1349578522617:dw|

54. Claire4christ

right

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see how it is lenght x divided by 90 feet

56. Claire4christ

ok i see now x/90

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that is a balanced equation if you divide that you get the same value as you did when you input cos of 50 into your calculator

58. Claire4christ

ok

59. Claire4christ

If the angle of declination changed to 60°, the cosine would be 0.5; now the length of x would be ________ feet.

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use the same equation with the cos of 60 instead

61. Claire4christ

so its gonna be cos(60)=x/90

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$\cos(60^{0})=\frac{ x }{ 90ft }$

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so now you need to solve for x

64. Claire4christ

so it would be 45

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yes one more blank left

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there is two ways to solve for this but you are suppose to use a trig function

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there are srry

68. Claire4christ

0.5

69. Claire4christ

If the angle of declination changed to 60°, the angle of inclination would be _____ degrees.

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no it wants to know the angle of inclination which is the angle from the bottom

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|dw:1349579030126:dw|

|dw:1349579070499:dw|

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the angel theta is unknown do you know which trig function to use to solve it

74. Claire4christ

not sure

75. Claire4christ

so theta is 60 degrees right

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if you look at the trig functions there are sin=opposite / hypotenuse cos which we covered and tangent = opposite / adjacent

77. Claire4christ

ok

78. Decart

so you want to use the sine function

From reading the problem, I believe you could solve simply from the fact you are working with a right triangle, and the sum of the two acute angles equals 90 degrees.

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|dw:1349579230668:dw|

81. Claire4christ

so apposite side is 45 right

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yes

83. Claire4christ

so we trying to find the bottom right

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yes the bottom angle

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on your calculator you push the 2nd button then 45/90

86. Claire4christ

i got 0.5

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you need the inverse sine of .5 which is 2nd sin .5

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are you using a ti calculator

89. Claire4christ

no my iphone

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you need to look for $\sin ^{-1}$

91. Claire4christ

ok

92. Claire4christ

you press sin ^-1

93. Claire4christ

and than 45/90

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is that a button

95. Claire4christ

yes its sin^(-1)

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yes what do you get when you put that in

97. Claire4christ

0.5

98. Decart

.5 is what you get when you do the division without the sine function I am not sure what your calculator is doing

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when you get the true inverse sine you will get 30 degrees

100. Claire4christ

i got 30

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that is correct know do you notice that the 30 you got and the 60 degree other angle add up to 90 and the right angle is also 90 every triangle has 180 degrees in it so you could have just found the missing amount from 180

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103. Decart

that is a link to a tutorial that might be able to help