Find the approximate value of b in the triangle shown.

13

12

8

5

Question

Find the approximate value of b in the triangle shown.





13

12

8

5

anonymous · Answer

https://clackamasweb.owschools.com/media/g_geo_ccss_2014/11/geo_10a_8_assess_media_2.gif

anonymous · Answer

use cosine law, have an idea what is it ?

anonymous · Answer

nope

anonymous · Answer

:O

anonymous · Answer

$b^2=a^2+c^2-2ac~ \cos B$

anonymous · Answer

b2=12^2+10^2−2ac cosB ?

anonymous · Answer

maybe u know it by its name "law of cosines"

anonymous · Answer

no i really dont:( dont really have had time to learn it

anonymous · Answer

its ok :) just memorize the formula and everything will be ok ur on the right track , u need to sub a and c as well like this http://prntscr.com/5uqic6

anonymous · Answer

here u can see this link also http://www.mathsisfun.com/algebra/trig-cosine-law.html

anonymous · Answer

i got 4 from it...

anonymous · Answer

:O how?

anonymous · Answer

12^2+10^2 - 2*12*10 cos 24 = 142

anonymous · Answer

how do i get it be one of my options?

anonymous · Answer

wait
$b^2= 12^2+10^2 - 2*12*10 cos 24 =24.74.....$
$b=\sqrt(24.74.....)=4.97...$ almost 5

when u said 4 like it was the right answer but i waned to be sure about approximation value

anonymous · Answer

ok thnx

anonymous · Answer

eh np