Question

Find the value of the sine for angle A.

Answer 1

what sides are used in sin(A) ?

Answer 2

a/12? so it would be 8.9/12?

Answer 3

yes a/12

we use pythagoras to find a: a^2+8^2= 12^2
or a^2= 144-64= 80
a= sqrt(80)
on a multiple choice they probably won't show sqrt(80)= 8.9442791
instead they would simplify sqrt(80) to sqrt(16*5)= sqrt(16)*sqrt(5)= 4*sqrt(5)
now
sin A = 4 *sqrt(5)/12 = sqrt(5)/3
follow?

Answer 4

Yes. That makes sense. So for cotangent I would do the same thing right?

Answer 5

except for cotangent it would be adjacent over opposite right?

Answer 6

to simplify the sqrt(80)
one way (if you did not notice 16 divides into it and 16 is a perfect square)
is break up 80 into prime factors
2*40 = 2*2 * 20= 2*2*2 * 10 = 2*2*2*2 *5
now "pull out pairs" there are 2 pairs of 2's so you pull them outside the sqrt, and only write 1 of each pair
\[ \sqrt{2\cdot 2\cdot 2\cdot 2\cdot 5}= 2\cdot 2\sqrt{5}= 4\sqrt{5}\]

Answer 7

Yeah. I know how to do that.

Answer 8

for cotangent A we need to know what sides
tan A = opp/adj = a/8
cot A is tan flipped so cot A= 8/a

Answer 9

Yeah. I know how to do that. oh, when I say you use 8.9 for sqrt(80) I thought you didn't....

Answer 10

Yeah. I just always try to use the decimal because it is easier to work with but I guess that is why I was not getting an answer.

Answer 11

Thank you so much for all your help!

Answer 12

what did you get for cot A ?

Answer 13

I was asking for a different questions where the hypotenuse was 10 the bottom leg was 8 and the side was 6. So then I got 8/6 which was 4/3. which was the correct answer.

Answer 14

but for Cot A on this one it would be 8/4sqr(5) then it would be 2/sqr(5)?

Answer 15

yes, but the catch is people don't like sqrt in the bottom so they multiply top and bottom by sqrt(5)
you get
\[\frac{2 \sqrt{5}}{5} \]

Answer 16

It only matters if it's multiple choice and you don't see 2/sqrt(5) as a choice

Answer 17

Ok.. Thank you. I have more questions would you be willing to help?

Answer 18

Trig is really hard for me. I am not sure why.

Answer 19

post the question

Answer 20

so close this question and post it as a new question?

Answer 21

yes, otherwise these things get long and confusing

Answer 22

haha! ok.