Question

The point (3, -4) is on the terminal side of an angle theta . What is cos theta ?

Answer 1

@tcarroll010 u got this

Answer 2

remember=

Answer 3

cosine is the x-coordinate divided by the length from (0,0) to (3, -4)

Answer 4

cos (-x) = cos (x)

So, you can go with @dpalnc 's drawing or make that -4 a +4 and just look at the first quadrant. That's what I do, but different people look at things differently. And since the cos is:

adjacent over hypotenuse

you look for the "x" value over the lenght of the hypotenuse and you use the Pythoagorean Theorem to get the length:

a^2 + b^2 = c^2

You already know "a" and "b".