YCIND_240528_6312_CBSE10_circle_2.png
 
In the figure:
 
ΔDEBΔACB by SSS similarity criterion.

\(BC\) \(=\) 30 \(cm\)
 
\(ED\) \(=\) 10 \(cm\)
 
\(AC\) \(=\) 30 \(cm\)
 
Then, \(BE\) \(=\)  \(cm\).