9. If $\sin \theta+\cos \theta$ $=\frac{7}{5}$, and $\tan \theta<1$, then $\sin \theta=$ $\qquad$
Obviously, $\theta$ is an angle in the first quadrant, and $\sin \theta < \cos \theta \Rightarrow \sin \theta$
$$
=\frac{3}{5} .
$$