70. As shown in the figure, on the two legs $AC$ and $BC$ of the right $\triangle ABC$, construct squares $ACDE$ and $CBFG$, respectively. Connect $DG$, connect $AF$ intersecting $BC$ at $W$, and connect $GW$. If $AC=14, BC=28$, then the area of $\triangle AGW$ is . $\qquad$
. Reference answer: 196