1. ## trig help?

i have to use either sin, cosine, or tangent?

2. ## Re: trig help?

$\sin(53deg)=\dfrac x {15}$

3. ## Re: trig help?

You need to learn by heart:

$\sin(\theta)$ is "opposite leg divided by hypotenuse".
$\cos(\theta)$ is "near leg divided by hypotenuse".
$\tan(\theta)$ is "opposite leg divided by near leg".

In your diagram the hypotenuse has length 15 and the side opposite the 53 degree angle has length x.