Triangle

Kiran · 2006-12-21 04:20:38

solve for x and y

*
* y *
* dg *
8 * * 10
* *
* *
* *
* *
* *
* *
* x degrees *
********************************
11

I did .. but i need your help!

p^2 = a^2 + b^2 - 2ab cos P
8^2 = 10^2 + 11^2 - 2 (10)(11) cos X
64 = 100 + 121 - 220 cos X
64 = 221 - 220 - cos X
221 - 64 = 157
157 = 220 cos X
0.7 = cos X
how many degrees is that?

and i know i have ot do this when i find teh degrees .....
to find y

8/sin(x) = 11/sin y

sin y = 11sin(x)/8

sin y = ________
and how much degrees is that?

PELASE HELP ME OUT

Last edited by Kiran (2006-12-21 05:20:55)

Stanley_Marsh · 2006-12-21 04:36:46

I think the p should be 10 , since the length p shoudn't be the adjacent to angle x

Last edited by Stanley_Marsh (2006-12-21 04:38:03)

Kiran · 2006-12-21 04:56:02

well i dont know...thats how they did it in the book

Stanley_Marsh · 2006-12-21 05:10:51

Is the length of the third side 11? is it given?

Kiran · 2006-12-21 05:21:12

oh god yeha..i forgot to put 11........thanks for reminding me

Last edited by Kiran (2006-12-21 05:21:50)

Kiran · 2006-12-21 05:22:15

can you help me out please?!

Stanley_Marsh · 2006-12-21 05:29:08

well follow the equality
10^2=8^2+11^2 - 2x8x11cosx
cosx=85/176

11^2=8^2+10^2-8x10x2cosy
cosy=43/160

That's my solution , Don't know if I am correct

Kiran · 2006-12-21 08:14:26

ok in my book they have the exact same question but offcourse with different numbers.
now i dont understand if we have such as in the book they have 0.5=cos x
and they said x = 60 degrees , 300 degrees and then they said x is less than 90 degrees so x = 60 degrees

how can i find the degrees of my problem?

luca-deltodesco · 2006-12-21 08:19:09

if you have

then you rearrange by taking the inverse cosine of both sides

or if you are in america

Last edited by luca-deltodesco (2006-12-21 08:19:42)

Kiran · 2006-12-21 08:24:33

ok guys i dont know...
can you show me what you might think will be the way in solving the problem?

Stanley_Marsh · 2006-12-21 16:04:07

The value of 0 dg , 30dg , 45dg , 90dg must be remembered , or you can draw a coordinate graph of triangle function or an acute triangle to find these values.

Math Is Fun Forum

#1 2006-12-21 04:20:38

Triangle

#2 2006-12-21 04:36:46

Re: Triangle

#3 2006-12-21 04:56:02

Re: Triangle

#4 2006-12-21 05:10:51

Re: Triangle

#5 2006-12-21 05:21:12

Re: Triangle

#6 2006-12-21 05:22:15

Re: Triangle

#7 2006-12-21 05:29:08

Re: Triangle

#8 2006-12-21 08:14:26

Re: Triangle

#9 2006-12-21 08:19:09

Re: Triangle

#10 2006-12-21 08:24:33

Re: Triangle

#11 2006-12-21 16:04:07

Re: Triangle

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