## anonymous one year ago If sin θ = 21/29 , use the Pythagorean Identity to find cos θ.

1. anonymous

$\cos \theta = \sqrt{1 - \sin \theta ^{2}}$

2. anonymous

i thought i needed to use sin^2+cos^2=1?

3. anonymous

oh wait thats the same thing isnt it....

4. anonymous

they are the same

5. campbell_st

just draw a triangle |dw:1436404771140:dw| find x using pythagoras then you can find the cos ratio

6. anonymous

i got now thx