$\begin{aligned}
& T=S_1 \
& \frac{x \cdot 1}{4}+\frac{y}{4}=\frac{1}{4}+\frac{1}{8} \
& \Rightarrow 2 x+2 y=3 \
& \frac{x^2}{4}+\frac{\left(\frac{3-2 x}{2}\right)^2}{2}=1 \
& \Rightarrow x=\frac{12 \pm \sqrt{120}}{12} \Rightarrow y=\frac{1}{2} \mp \frac{\sqrt{120}}{12}
\end{aligned}Solengthofchord=\frac{2 \sqrt{15}}{3}$