What is the value of sinθ given that (−3,4) is a point on the terminal side of θ ?



−3/5

3/5

4/5 <my answer

−4/5

3 answers

Draw your triangle in standard position. It is clearly a 3-4-5 right triangle.

sinθ = y/r
I'm still a bit confused
Huh? You are in trig, and cannot tell what the x- and y- coordinates are?

The point (-3,4) is at
x = -3
y = 4
since r^2=x^2+y^2, r=5.

sinθ = y/r = 4/5

You got the right answer; was it just a guess?