17)AD=lățime
AB=AD×2
AB=6cm×2
AB=12cm12cm
P=AB+CD
P=12cm+6cm
P=18cm
A=2×(AB+AD)
A=2×(12cm+6cm)
A=2×18cm
A=36cm²
AC=6cm(AB-AD)
19)toate laturile rombului sunt concurente
A=
[tex] \frac{ac \times bd}{2} = \frac{6 \times 6}{2} = \frac{36}{2} = 18[/tex]
