## jjuden one year ago What is the length of side AB if AC is 5 sqrt 2?

1. jjuden

2. jjuden

a. 5m b. 5 sqrt 2 m c. 5 sqrt 3 m d. 10m

3. xapproachesinfinity

use cosine

4. Nnesha

you should use cos which is equal =adjacent over hyp $\huge\rm cos 45 = \frac{ x }{ 5\sqrt{2} }$ http://openstudy.com/study#/updates/5575da3ce4b0826b0eaf6c46

5. xapproachesinfinity

what is cos(45)=?

6. jjuden

i think its c but my math is off

7. anonymous

|dw:1433788042810:dw|

8. Nnesha

nope c is wrong and remember it's 45 degree*

9. anonymous

$2 x^2=\left(5 \sqrt{2}\right)^2$ x = 5

10. anonymous

you can use pythagoras's theorem $x^2+x^2=\left( 5\sqrt{2} \right)^2,x=?$

11. jjuden

thank you all i think i got it :)