Question

Please help! Solve for the missing length and the other two angles in the triangle below

Answer 1

@ranga

Answer 2

First, use the Law of Cosines to find the length of the side opposite to the 5 degree angle.

Answer 3

it is 15 degrees

Answer 4

okay use 15 degrees in the formula.

Answer 5

I don't know where a , b , c are though

Answer 6

ok thanks hold on

Answer 7

so a^2=3^2 + 4^2 -2(3)(4)cos(15)

Answer 8

Yes.

Answer 9

so do I do a=sqrt of all that?

Answer 10

Yes.

Answer 11

After you find 'a', use the law of sines to find angle B:
a / sin(A) = b / sin(B)
Then angle C = 180 - (angle A + angle B)

Answer 12

a= 1.348?

Answer 13

Yes.

Answer 14

ok, 15.642=sin(B) ?

Answer 15

@ranga

Answer 16

Solve for angle B.

Answer 17

I don''t know how @ranga sin^-1(15.642) is undefined

Answer 18

15.64 was degrees? you want me to do sin^-1(.273)?

Answer 19

the problem is that sin^-1(15.642) is not showing any number

Answer 20

Oh, Your calculation is wrong. It cannot be 15.642. Redo that calculation because sine cannot be more than 1.

Answer 21

a / sin(A) = b / sin(B)
sin(B) = b * sin(A) / a = 3 * sin(15) / 1.348 =

Answer 22

Since angle A is 15 degrees, set your calculator to degree mode.

Answer 23

31.17 degrees. ok thanks man

Answer 24

I am getting 35.17 degrees.

Answer 25

sin^-1(.576) = .6138 radians = 31.17 degrees

Answer 26

Check my comment above. The angle 15 is in degrees. SO you have to set the calculator to degree mode BEFORE you calculate 3 * sin(15) / 1.348
Then when you take the inverse the answer will be in degrees because your calculator is already set to degree mode.

Answer 27

I'm using wolfram I don't have a calculator near me

Answer 28

@ranga

Answer 29

If I use wolfram I still get 35.17 degrees.
3 * sin(15) / 1.348 = 0.576
arcsin(0.576) = 35.17 degrees.