Question

http://prntscr.com/arwka7
Can someone check my answer?

For BA I got 36, but it doesn't seem right. I used tangent.

Answer 1

I haven't solved for A. This is just concerning the side BA.

Answer 2

what is your idea for solve it ?

Answer 3

Hmm, that's not what I got. Can you show working?

Answer 4

Alright! I set it up as tan52=x/28 which turned into 28(tan52)=x

Answer 5

It was 35.8283 which I rounded to get 36 because we round quite a bit at my school.

Answer 6

The triangle is not a right-angled triangle so you can't apply your tan formula. As the question says, you need to use the law of cosine :P Do you know the law of cosine?

Answer 7

I do! : )

And ah, I see what I did wrong.

Answer 8

Don't I need to find BA to use law of cosines?

Answer 9

Nope, in fact, you HAVE to use the law of cosines to find BA

Answer 10

And then you can use law of cosines again, after you've found BA :P

Answer 11

I only know how to use it to find the angle. Could you guide me through it to find BA?

Answer 12

But this isn't a right triangle?

How can we use it?
@surjithayer

Answer 13

i do not say it is a right angle.

Answer 14

correction write 25 in place of 28

Answer 15

Can you show me using the law of cosines?

I'm not sure what you're doing up there haha.

Answer 16

I'm familiar with laws of cosine and cosine, but I'm not sure what you're doing.

http://prntscr.com/arx294

This is the form I am familiar with.

Answer 17

ok l will show it is the same.

Answer 18

Alright, continue.

Though, continue to use my form. : )

Answer 19

\[29^2=25^2+28^2-2\times 25\times 28 \cos A\]
841=625+784-1400 cos A
find cos A then take its inverse to find <A

Answer 20

Question, how did you get BA?

@surjithayer

Answer 21

i have already found BA above
BA=x