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Math Help - Need help have worked out these problems need to see if I got them correct

  1. #1
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    Nov 2011
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    Need help have worked out these problems need to see if I got them correct

    Ok so here are the questions with my answers

    Tell how many triangles there are and solve each triangle completely

    1 angle a equals 39.7 degrees angle c equals 91.6 degrees the length
    of b equals 16.4
    ---angle b=48.7 degrees
    ---a=13.9
    ---c=21.8
    ---# of triangles -------idk------------

    2 angle a equals 39.7 degrees side c equals 18.4 side a equals 3.7
    ---angle c=3.2 degrees
    ---angle b=137.2 degrees
    ---b=3.9
    ---# of triangles 0 # of triangles is definitely correct i found the
    answer in the book

    3 angle a equals 41.2 degrees side a equals 8.1 side b equals 10.6
    ---angle c=79.3 degrees
    ---angle b=59.5 degrees
    ---c=12.1
    ---# of triangles 2
    the second triangle
    ---angle b=120.5 degrees
    ---angle c=18.3 degrees
    ---c=3.9

    how i got the second triangle because for an SSA example having side a
    side b and angle a
    1. find h=bsinangleA if h>a there is no triangle
    2. if h=a there is one right triangle angle b is 90 degrees and side b
    is hypotenuse solve using right angle trig
    3. if h<a<b there are 2 triangles one with angle b acute and one with
    angle b obtuse. find the acute b using law of sines. subtract it from
    180 degrees to get the obtuse angle b. in each of the two triangles
    find angle y using angle y=180 degrees-angle a-angle b and side c using
    law of sines
    4 if a is greater than or equal to b there is only one triangle and
    angle b is acute (angle a or angle y might be obtuse) find angle b
    using law of sines then find angle y using y=180-angle a-angle b. find
    c using law of sines

    **************************ISSUE ANGLE B IS SUPPOSED TO BE ACUTE BUT IT
    IS NOT IT IS 59.5 DEGREES WHILE ANGLE A IS 41.2 DEGREES WHAT DID I DO
    WRONG**************************

    4 I got this answer for sure correct

    Solve each triangle completely

    5 side a equals 4.1 side b equals 9.8 side c equals 6.2
    ---angle a=14.4 degrees
    ---angle b=143.4 degrees
    ---angle y=22.2 degrees

    6 angle a equals 20 degrees angle c equals 120 degrees side b equals
    12.3
    ---a=6.5
    ---angle b=40 degrees
    ---c=16.6

    7 find the area of number 5 using heron's formula
    ---Area=7.6

    8 i got this answer for sure correct

    9 i got this answer for sure correct

    10 find the magnitude of the horizontal and vertical components |v|=4.5
    and o with a line thru it equals 60
    ---lVyl=3.9
    ---lVxl=2.3

    11 find the magnitude and direction of angle v. V=<-4,-2> give the
    exact value for magnitude and round direction angle to the nearest 10th
    of a degree
    ---magnitude i got was the sqrt of 20 but then i reduced it to 2sqrt5
    does that mean exact value?
    ---i do not know the direction angle (I am confused because I know that you use x=tan^-1(2/4)= a number but then I am not sure if I have to suntract that number from 180, 90, 360 or nothing

    12 for the given pair of vectors find the magnitude and direction angle
    of the resultant
    <4,2> <-6,6>
    ---magnitude i got sqrt68 then reduced it to 2sqrt17
    ---i do not know the direction angle
    ---also how do i draw the new line? would it just be <-2,8>?

    13 a plane is headed due west with an air speed of 240 miles per hour.
    the wind is coming from the north at 30 miles per hour. find the
    bearing for the course and the ground speed of the plane.
    *******THERE IS A PROBLEM JUST LIKE THIS ONE IN THE BOOK EXCEPT IT SAYS
    THE PLANE IS HEADED DUE EAST INSTEAD OF WEST DOES THE AFFECT THE
    ANSWER********
    if notttttttt the answer in the book is
    ---bearing=97.1 degrees
    ---ground speed=241.9mph


    ****thank you soooo much for your help!!! if you have any questions just message!
    Last edited by smilez750; November 13th 2011 at 10:11 AM.
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  2. #2
    Flow Master
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    Dec 2007
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    Re: Need help have worked out these problems need to see if I got them correct

    Quote Originally Posted by smilez750 View Post
    Ok so here are the questions with my answers

    Tell how many triangles there are and solve each triangle completely

    1 angle a equals 39.7 degrees angle c equals 91.6 degrees the length
    of b equals 16.4
    ---angle b=48.7 degrees
    ---a=13.9
    ---c=21.8
    ---# of triangles -------idk------------

    2 angle a equals 39.7 degrees side c equals 18.4 side a equals 3.7
    ---angle c=3.2 degrees
    ---angle b=137.2 degrees
    ---b=3.9
    ---# of triangles 0 # of triangles is definitely correct i found the
    answer in the book

    3 angle a equals 41.2 degrees side a equals 8.1 side b equals 10.6
    ---angle c=79.3 degrees
    ---angle b=59.5 degrees
    ---c=12.1
    ---# of triangles 2
    the second triangle
    ---angle b=120.5 degrees
    ---angle c=18.3 degrees
    ---c=3.9

    how i got the second triangle because for an SSA example having side a
    side b and angle a
    1. find h=bsinangleA if h>a there is no triangle
    2. if h=a there is one right triangle angle b is 90 degrees and side b
    is hypotenuse solve using right angle trig
    3. if h<a<b there are 2 triangles one with angle b acute and one with
    angle b obtuse. find the acute b using law of sines. subtract it from
    180 degrees to get the obtuse angle b. in each of the two triangles
    find angle y using angle y=180 degrees-angle a-angle b and side c using
    law of sines
    4 if a is greater than or equal to b there is only one triangle and
    angle b is acute (angle a or angle y might be obtuse) find angle b
    using law of sines then find angle y using y=180-angle a-angle b. find
    c using law of sines

    **************************ISSUE ANGLE B IS SUPPOSED TO BE ACUTE BUT IT
    IS NOT IT IS 59.5 DEGREES WHILE ANGLE A IS 41.2 DEGREES WHAT DID I DO
    WRONG**************************

    4 I got this answer for sure correct

    Solve each triangle completely

    5 side a equals 4.1 side b equals 9.8 side c equals 6.2
    ---angle a=14.4 degrees
    ---angle b=143.4 degrees
    ---angle y=22.2 degrees

    6 angle a equals 20 degrees angle c equals 120 degrees side b equals
    12.3
    ---a=6.5
    ---angle b=40 degrees
    ---c=16.6

    7 find the area of number 5 using heron's formula
    ---Area=7.6

    8 i got this answer for sure correct

    9 i got this answer for sure correct

    10 find the magnitude of the horizontal and vertical components |v|=4.5
    and o with a line thru it equals 60
    ---lVyl=3.9
    ---lVxl=2.3

    11 find the magnitude and direction of angle v. V=<-4,-2> give the
    exact value for magnitude and round direction angle to the nearest 10th
    of a degree
    ---magnitude i got was the sqrt of 20 but then i reduced it to 2sqrt5
    does that mean exact value?
    ---i do not know the direction angle (I am confused because I know that you use x=tan^-1(2/4)= a number but then I am not sure if I have to suntract that number from 180, 90, 360 or nothing

    12 for the given pair of vectors find the magnitude and direction angle
    of the resultant
    <4,2> <-6,6>
    ---magnitude i got sqrt68 then reduced it to 2sqrt17
    ---i do not know the direction angle
    ---also how do i draw the new line? would it just be <-2,8>?

    13 a plane is headed due west with an air speed of 240 miles per hour.
    the wind is coming from the north at 30 miles per hour. find the
    bearing for the course and the ground speed of the plane.
    *******THERE IS A PROBLEM JUST LIKE THIS ONE IN THE BOOK EXCEPT IT SAYS
    THE PLANE IS HEADED DUE EAST INSTEAD OF WEST DOES THE AFFECT THE
    ANSWER********
    if notttttttt the answer in the book is
    ---bearing=97.1 degrees
    ---ground speed=241.9mph


    ****thank you soooo much for your help!!! if you have any questions just message!
    MHF does not act as a checking service for a list of questions this long. I suggest you hand in your work and wait for feedback from your teacher.

    Thread closed.
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