Write the ratio for $\sin A$. \[ \sin A= \] (Type an integer or a simplified fraction.)

Step 1 ：Recall the definition of sine in a right triangle: \(\sin A = \frac{\text{opposite side}}{\text{hypotenuse}}\)

Step 2 ：In our case, the side opposite angle A is 3 and the hypotenuse is 5, so \(\sin A = \frac{3}{5}\)

Step 3 ：\(\boxed{\sin A = \frac{3}{5}}\)