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

• Nov 13th 2011, 09:10 AM
smilez750
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

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
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!
• Nov 13th 2011, 10:14 AM
mr fantastic
Re: Need help have worked out these problems need to see if I got them correct
Quote:

Originally Posted by smilez750
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

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