Question

Answer 1

Áp dụng định lý Ta-lét ta có:

\(\dfrac{ID}{IE}=\dfrac{DK}{KF}\\ \Rightarrow\dfrac{x}{6}=\dfrac{4}{8}\\ \Rightarrow x=\dfrac{4}{8}.6\\ \Rightarrow x=3\left(cm\right)\)

Áp dụng định lý Ta-lét ta có:

\(\dfrac{IK}{EF}=\dfrac{DK}{KF}\\ \Rightarrow\dfrac{y}{18}=\dfrac{4}{12}\\ \Rightarrow y=\dfrac{1}{3}.18\\ \Rightarrow y=6\left(cm\right)\)

Answer 2

Xét ΔDEF có IK//EF

nen x/6=4/8=1/2

=>x=3(cm)

Xét ΔDEF có IK//EF

nen y/18=1/3

=>y=6(cm)

 

Answer 3

Theo định lí Ta lét 

\(\dfrac{DI}{IE}=\dfrac{DK}{KF}\Rightarrow\dfrac{x}{6}=\dfrac{4}{8}\Rightarrow x=3\)cm 

Theo hệ quả Ta lét 

\(\dfrac{DK}{DF}=\dfrac{IK}{EF}\Rightarrow IK=\dfrac{4.18}{12}=6\)cm