2026 HSC CHAT (7 Viewers)

[isho-3]

Can anyone do this question (5.a.) for me? (Using the sine rule for finding angles)
View attachment 44383

sina/8 = sin42/6
a = sin^-1(8sin42/6)
a = 63.14...
theta = 180 - 42 - 63 = 75

yeah, it's 75 degrees. for this question, don't use the sine rule twice; the theta is not the subject of the sine rule in this equation, and therefore can be solved by simply using the missing angle formula for triangles with two known angles.

 

[ellurbee]

Ha

Apparently the answer is “75 degrees or 117 degrees”
Though i don't see how it can be 117 degrees considering the question says that theta is acute

Have you heard of the Ambiguous case?
*I'm looking at my notes and Ambiguous means 'not clear' or 'undecided' meaning that B could have two answers- an acute answer or an obtuse answer*

 

[jane1820]

What answer did you get? Just 75 or something else?

I got 63 degrees
i did the following steps: (also i swear my handwriting looks better on paper )

 

[isho-3]

Ha

Have you heard of the Ambiguous case?
*I'm looking at my notes and Ambiguous means 'not clear' or 'undecided' meaning that B could have two answers- an acute answer or an obtuse answer*
View attachment 44384

yeah this is valid,,,,, but i don't think they'd use an ambiguous case in tests? at least, if they are, it'd be a bit of a dirty trick. the question in the (i'm assuming) textbook is pretty open, and you'd probably have to ask later in the test (if they include something like it) about whether they want you to solve the theta for the given triangle or the given information

 

[jane1820]

sina/8 = sin42/6
a = sin^-1(8sin42/6)
a = 63.14...
theta = 180 - 42 - 63 = 75

yeah, it's 75 degrees. for this question, don't use the sine rule twice; the theta is not the subject of the sine rule in this equation, and therefore can be solved by simply using the missing angle formula for triangles with two known angles.

Hmm but why did u do that? (Im not even up to there i just skipped a few chapters to the sine rule so can u educate me a little?)

 

[jane1820]

Ha

Have you heard of the Ambiguous case?
*I'm looking at my notes and Ambiguous means 'not clear' or 'undecided' meaning that B could have two answers- an acute answer or an obtuse answer*
View attachment 44384

Yh but the question says that theta is an acute not like it didnt specify (?)

 

[isho-3]

I got 63 degrees
i did the following steps: (also i swear my handwriting looks better on paper )
View attachment 44385

you missed a step; the answer you got is correct, but it's not what you're solving for. you got the 2nd unknown angle in the triangle, but not the value of theta itself. from here you need to solve for theta using missing angles in a triangle w/ 2 known angles (180 - 63 - 42 = 75). basically you weren't wrong in the answer for the other unknown angle (i've dubbed angle 'a' in my solution), but forgot to solve for theta afterwards.

 

[jane1820]

you missed a step; the answer you got is correct, but it's not what you're solving for. you got the 2nd unknown angle in the triangle, but not the value of theta itself. from here you need to solve for theta using missing angles in a triangle w/ 2 known angles (180 - 63 - 42 = 75). basically you weren't wrong in the answer for the other unknown angle (i've dubbed angle 'a' in my solution), but forgot to solve for theta afterwards.

what do u mean by ‘value’? Help im lost
isnt when u say (for example) a=3 in an equation doesnt that mean the value of a is 3?

 

[sly_lyepat]

I got 63 degrees
i did the following steps: (also i swear my handwriting looks better on paper )
View attachment 44385

You have to solve the angle opposite to the missing side, the angle you just found is opposite to 8 , so minus the answer form the angle you just found from 180 so you do:
180-63-42=75
180(sum of all angles in a triangle)-63(angle you just solved)-42(angle they all ready gave)=75(theta)

 

[IStrokeItDaily69]

ok

 

[jane1820]

You have to solve the angle opposite to the missing side, the angle you just found is opposite to 8 , so minus the answer form the angle you just found from 180 so you do:
180-63-42=75
180(sum of all angles in a triangle)-63(angle you just solved)-42(angle they all ready gave)=75(theta)

OHHH IT ALL MAKES SENSE NOW OMG THX

 

[jane1820]

Wait also guys so when we got that theta is 75 degrees why does the answer say ‘75 degrees or 117 degrees’? I get that 180-63 is 117 but that doesnt make any sense in addition to the question saying that theta is an acute angle, how does that work?

 

[Shavi Masee]

I am now motivated to do some math!!

 

[jane1820]

I am now motivated to do some math!!

I LOVE MATH RHAHAHAHAHAH

 

[jane1820]

I am now motivated to do some math!!

What topic r u guys doing rn at ur skl? Also ur 5.3 yh?

 

[ellurbee]

we just finished surds in the last week of school. Hbu?

Shavi- Do you think they're gonna put ambiguous cases in our Yearly- Imma cry if they don't specify cause that's dirtyyyy

 

[Shavi Masee]

Shavi- Do you think they're gonna put ambiguous cases in our Yearly- Imma cry if they don't specify cause that's dirtyyyy

fr imma cry T-T
I'll do a few questions of those just to make sure

 

[jane1820]

we just finished surds in the last week of school. Hbu?

last thing was trig (im catching up) N then financial math then our yearlies

 

[jane1820]

Shavi- Do you think they're gonna put ambiguous cases in our Yearly- Imma cry if they don't specify cause that's dirtyyyy

When is ur yearly?

 

[Shavi Masee]

last thing was trig (im catching up) N then financial math then our yearlies

What do you mean by catching up?
I absolutely despise financial math. It's not hard but i just despisee it so much ughhh. fingers crossed we don't get to that topic before yearlies