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anonymous

  • one year ago

PLEASE HELP: MEDAL AND FAN Solve the triangle. A = 51°, b = 11, c = 7

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  1. anonymous
    • one year ago
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    @campbell_st

  2. anonymous
    • one year ago
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    can you help? @swamijatin2

  3. swamijatin2
    • one year ago
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    what we have to find perimeter or area

  4. anonymous
    • one year ago
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    neither

  5. anonymous
    • one year ago
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    lol wrong thing sorry

  6. anonymous
    • one year ago
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    I need a (side a); C(angle c); and B(angle b)

  7. anonymous
    • one year ago
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    @campbell_st

  8. anonymous
    • one year ago
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    ok

  9. swamijatin2
    • one year ago
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    or well that doesnt have to be a right triangle but

  10. anonymous
    • one year ago
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    now what

  11. anonymous
    • one year ago
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    @satellite73

  12. anonymous
    • one year ago
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    how do i do this

  13. anonymous
    • one year ago
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    draw a triangle that looks reasonably like this one then use the law of cosines

  14. anonymous
    • one year ago
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    i have a triangle but how do i use the law of cosines (i know what it is just not how to do it)

  15. anonymous
    • one year ago
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    \[a^2=b^2+c^2-2bc\cos(A)\] \[a^2=11^2+7^2-2\times 11\times 7\cos(51^\circ)\] and a calculator

  16. swamijatin2
    • one year ago
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    To solve the traingle we need to find remaining side a and angles B and C. Use law of cosines a2 = b2 + c2 - 2bc cosA a2 = (11)2 + (7)2 - 2(11)(7) cos(51) a2 = 121 + 49 - 154 cos(51) a2 = 170 - 154(0.629) a2 = 170 - 96.866 a2 = 73.134 a = 8.55

  17. anonymous
    • one year ago
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    i got that ok so how about the and C

  18. anonymous
    • one year ago
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    B and C angles

  19. swamijatin2
    • one year ago
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    Now use law of sines sinA/a = sinB/b sin(51)/ 8.55 = sin(B)/11 sin(B) = 11[sin(51)/ 8.55] sin(B) = 11[0.777/8.55] B = sin-1(0.999) B = 87.43°

  20. anonymous
    • one year ago
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    ok and C?

  21. swamijatin2
    • one year ago
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    Sum of angles in triangle = 180° A + B + C = 180 C = 180 - (A + B) C = 180 - (51 + 87.43) C = 180 - 138.43 C = 41.57°

  22. anonymous
    • one year ago
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    http://www.wolframalpha.com/input/?i=sqrt%2811^2%2B7^2-2*11*7*cos%2851%29%29

  23. anonymous
    • one year ago
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    because none of those are my answers

  24. swamijatin2
    • one year ago
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    then you are incorrect anywhere

  25. anonymous
    • one year ago
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    what?

  26. swamijatin2
    • one year ago
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    did u get the answers

  27. anonymous
    • one year ago
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    8.5 is a which is only for one answer choice where B = 85.9 and C = 39.1

  28. anonymous
    • one year ago
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    a ≈ 12.8, C ≈ 39.1, B ≈ 89.9 a ≈ 8.5, C ≈ 39.1, B ≈ 89.9 No triangles possible a ≈ 12.8, C ≈ 43.1, B ≈ 85.9

  29. swamijatin2
    • one year ago
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    you r correct but according to question we have to do

  30. anonymous
    • one year ago
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    @Loser66

  31. anonymous
    • one year ago
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    please finish helping me @swamijatin2

  32. anonymous
    • one year ago
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    @phi

  33. anonymous
    • one year ago
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    we have done a lot but it doesn't match my answer choices

  34. phi
    • one year ago
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    can you re-post the question and the answer you got? It would take a long time to read through all of the posts up above.

  35. anonymous
    • one year ago
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    sure hold on

  36. anonymous
    • one year ago
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    Solve the triangle. A = 51°, b = 11, c = 7

  37. anonymous
    • one year ago
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    Work From above: a2 = b2 + c2 - 2bc cosA a2 = (11)2 + (7)2 - 2(11)(7) cos(51) a2 = 121 + 49 - 154 cos(51) a2 = 170 - 154(0.629) a2 = 170 - 96.866 a2 = 73.134 a = 8.55 Now use law of sines sinA/a = sinB/b sin(51)/ 8.55 = sin(B)/11 sin(B) = 11[sin(51)/ 8.55] sin(B) = 11[0.777/8.55] B = sin-1(0.999) B = 87.43° Sum of angles in triangle = 180° A + B + C = 180 C = 180 - (A + B) C = 180 - (51 + 87.43) C = 180 - 138.43 C = 41.57°

  38. anonymous
    • one year ago
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    My answer choices are: a ≈ 12.8, C ≈ 39.1, B ≈ 89.9 a ≈ 8.5, C ≈ 39.1, B ≈ 89.9 No triangles possible a ≈ 12.8, C ≈ 43.1, B ≈ 85.9

  39. anonymous
    • one year ago
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    so... what do we do?

  40. phi
    • one year ago
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    side a is correct. a= 8.55 redo your work for angle B

  41. phi
    • one year ago
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    the problem is when you do the work for angle B, you need lots of decimals of accuracy. for side a, don't round it to 8.55. use all the digits your calculator has.

  42. anonymous
    • one year ago
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    ok

  43. phi
    • one year ago
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    it might be more accurate to first find angle C sin C = (7*sin51)/8.548956649

  44. anonymous
    • one year ago
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    what do you get for angle B i got the same answer

  45. anonymous
    • one year ago
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    I got 0.63633750 Radians for C?

  46. phi
    • one year ago
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    sin C = 0.63633750 C= asin( 0.63633750 ) = 39.519 deg

  47. phi
    • one year ago
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    summarizing a= 8.55, b= 11, c= 7 A= 51, B= 89.5, C= 39.5 the best match to your choices is choice B

  48. phi
    • one year ago
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    if we use a=8.6 (round from 8.55) we would get C= 39.2 and B= 89.8 which is even closer to choice B.

  49. phi
    • one year ago
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    because they use ≈ which means approximately it is reasonable to pick choice B. And the other choices are not "in the ball park"

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