THe first thing we need to do is find the hypotenuse. From the tangent we know that the legs of the right triangle are 3 and 4. So this 2/3 of a special right triangle (3-4-5). Thus the hypotenuse is 5. The sin is defined as [tex] \frac{opposite}{hypotenuse} [/tex]. We know the opposite is 4 and hypotenuse is 5. Thus the sin is [tex]- \frac{4}{5} [/tex]
