Question

  

Tim x, y

72

(CAB)(DE)

Answer 1

Xét ΔCAB và ΔCED có

\(\widehat{CAB}=\widehat{CED}\)(hai góc so le trong, AB//ED)

\(\widehat{ACB}=\widehat{ECD}\)(hai góc đối đỉnh)

Do đó: ΔCAB~ΔCED
=>\(\dfrac{CA}{CE}=\dfrac{CB}{CD}=\dfrac{AB}{ED}\)

=>\(\dfrac{3}{y}=\dfrac{x}{7,2}=\dfrac{5}{DE}\)

=>\(\left\{{}\begin{matrix}x=\dfrac{36}{DE}\\y=\dfrac{3DE}{5}\end{matrix}\right.\)