Question

If sin Θ = 21 over 29, use the Pythagorean Identity to find cos Θ.

cos Θ = ± 8 over 29

cos Θ = ± 21 over 20

cos Θ = ± 29 over 20

cos Θ = ± 20 over 29

Answer 1

If you're good in fractions it's easy

Answer 2

ive got a calculator that is how would i go about it

Answer 3

is the sin suppose to be sin^2 theta?

Answer 4

no just sin theta

Answer 5

ok

Answer 6

give me a minute to work it out

Answer 7

Are there options?

Answer 8

you should draw a right triangle, and label the sides

using the idea that
sin(angle) = opposite/hypotenuse

Answer 9

that's too much work. I would write it in an equation

Answer 10

what do you mean by sin = opposite

Answer 11

sin is opposite over hypotenuse

if this does not ring any bells you should watch
http://www.khanacademy.org/math/trigonometry/basic-trigonometry/basic_trig_ratios/v/basic-trigonometry

Answer 12

when they tell you
sin Θ = 21 over 29,

that tells you the "opposite side" is 21
and the 29 is the hypotenuse

draw a triangle and fill in these numbers