Finding Sin r from 1.52 and 20 Degrees

[Novus Dakota]

so my given is 1.52 20degrees = 1.10 sin r

im trying to find sin r which comes out to 18.9 degrees but I am not sure how find that, can somebody help me out please?

so you do 1.10/1.52

do you divide that into sin 20?

 

[Jameson]

I don't quite understand your notation...

Is that first part : 1.52 * 20 deg?

 

[Novus Dakota]

snells law is n1 sin i = n2 sin r

n1= 1.52
sin i = 20 deg

n2 = 1.10

sin r = ?

sin r actually equals 28.2 deg but i don't understand the process

 

[Jameson]

Isn't this just simple algebra? What do you get when you solve for the unknown variable?

 

[Jameson]

I got 27.6 as my answer...

 

[Data]

...

$$\sin{x}$$ does not give you an answer in degrees.

$$n_1 \sin{\theta_1} = n_2 \sin{\theta_2} \Longrightarrow \theta_1 = \sin^{-1}\left( \frac{n_2}{n_1} \sin{\theta_2}\right)$$

 

[Jameson]

Isn't the question what is sin r? Not what is the angle...

 

[Data]

Well, in that case he's in for a surprise if he wants it to "come out to $$18.9^\circ$$"

 

[Novus Dakota]

but how do you do it

1.10/1.52 =.723

sin 20=.723

then I am stuck...

 

[Data]

Look for the $$\sin^{-1}$$ button on your calculator. Apply it as in the equation I put above.

 

[K.J.Healey]

first calculate sin(20)
then multiply that by 1.52
then divide by 1.10
then take the arcsin/inverse sin of that number
make sure its in degrees and yorue done.

28.2