Trig Problems

Question

If
cos(θ) = 7/ 18
with θ in Quadrant I, what is sin(θ)?

Answer 1

5*sqrt(11) / 18

 

 

The triangle has base along the x - axis of 7

The hypotneuse is 18.

 

Using the pythagorean theorem in reverse:

  18^2 = y^2 + 7^2

 

  324 = y^2 + 49

 

 225 = y^2

 

 25 * 11  = y^2

 

 y = 5*sqrt(11)   is the height and the opposite side of the angle

 

So the sine is 5*sqrt(11)/18