Question

Solve the triangle.

B = 73°, b = 15, c = 8

Answer 1

C = 35.9°, A = 71.3°, a ≈ 15.2

C = 30.7°, A = 76.3°, a ≈ 15.2

C = 30.7°, A = 76.3°, a ≈ 21.3

Cannot be solved

Answer 2

@Traxter

Answer 3

I'm sure you can set up an equation using the Sine rule now.

Answer 4

a/sina=b/sin73=8/sinC

Answer 5

You know what b is as well, substitute this in and then use the last 2 equations to find the angle C.

Answer 6

a/sina=15/sin73=8/sinC

Answer 7

Yes, so use the second 2 equations to find what C is.

Answer 8

sinC= 15sin73/8sin? i always have trouble with this part.

Answer 9

You have:
\[\frac{15}{sin73}=\frac{8}{sinC}\]
I'll try another path of thought that may make more sense to you. Divide both sides by 8 to get:
\[\frac{15}{8sin73}=\frac{1}{sinC}\]
Then flip the fractions round to get:
\[sinC=\frac{8sin73}{15}\]

Answer 10

and then when i put it into wolf?

Answer 11

Apply sin^-1 to the right hand side to find the value of C. You should be able to write this now.

Answer 12

(8sin73/15)sin^-1 ??

Answer 13

No. It will be sin^-1((8sin73)/15). Can you see why?

Answer 14

0.53? http://www.wolframalpha.com/input/?i=sin%5E-1%28%288sin73%29%2F15%29

Answer 15

Nope. You should be looking where it says conversion from radians to degrees.

Answer 16

30.67. yet thats not an option

Answer 17

oh i have to round!

Answer 18

well then i know its either one of these...
C = 30.7°, A = 76.3°, a ≈ 15.2

C = 30.7°, A = 76.3°, a ≈ 21.3

Answer 19

Yep, so you can now find the size of angle A using the interior angle sum formula and then use the Sine rule again to find the size of angle a.

Answer 20

im sorry, i know weve done this like 2 times before already, but i still cant remember how to do that.

Answer 21

I know you can set up the Sine rule using those sides to find the length of side a.

Answer 22

do i add 15+8 and subtract that from 73?

Answer 23

No, why would you do that?

Answer 24

idk, im loosing my mind!

Answer 25

Use the sine rule:

Does that help?

Answer 26

a/sinA=15/sinB=8/sinC ?

Answer 27

Yes, but you know what angles A, B and C are.