Question

In trapezul isoscel ABCD , AB=CD=4 cm , AD=
$\frac{4}{5} \times bc = 8cm$
Perimetrul trapezul este egal cu:
a) 16 cm
b)24 cm
c)26 cm
d)20 cm​.

Answer 1

Răspuns: $\bf Perimetrul_{ABCD}= 26\:cm$

Explicație pas cu pas:

Salutare!

Trapezul isoscel ABCD

$\bf AB = CD = 4\:cm$

$\bf AD = 8\:cm \: (baza \: mica)$

$\bf AD = \dfrac{4}{5}\cdot BC = 8\:cm$

$\bf \dfrac{4}{5}\cdot BC = 8\:cm\:\Big|\cdot 5\implies4\cdot BC=8\cdot 5\implies4\cdot BC=40\:\Big|:5\implies\boxed{\bf BC=10\:cm}$

$\bf Perimetrul_{ABCD}= AB+BC+CD+AD$

$\bf Perimetrul_{ABCD}= 4\:cm+10\:cm+4\:cm+8\:cm$

$\boxed{ \boxed {\bf Perimetrul_{ABCD}= 26\:cm}}$

Varianta c) 26 cm

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