BC//DE nên theo định lí Talet ta có:
\(\dfrac{AB}{BD}=\dfrac{AC}{CE}\)
=>CE=\(AC\cdot\dfrac{BD}{AB}=3\cdot\dfrac{4}{2}=6\left(cm\right)\)
ta có BC//De, Áp dụng định lý talet ta có:
\(\dfrac{AB}{BD}\)= \(\dfrac{AC}{CE}\)
=> CE=AC.\(\dfrac{BD}{AB}\)
= 3. \(\dfrac{4}{2}\)=6(cm)