Answer:
Step-by-step explanation:
Look at the picture.
ΔABC and ΔEBD are similar (AA). Therefore the sides are in proportion:
[tex]\dfrac{AB}{EB}=\dfrac{AC}{ED}[/tex]
We have
[tex]AB=40cm\\EB=x\\AC=32cm\\ED=4cm[/tex]
Substitute:
[tex]\dfrac{40}{x}=\dfrac{32}{4}[/tex] cross multiply
[tex]32x=(40)(4)[/tex]
[tex]32x=160[/tex] divide both sides by 32
[tex]x=5[/tex]