[tex]\displaystyle
A_{_{\Delta ABC} } = \frac{AB\times h}{2}= \frac{11\times 9}{2}=\frac{99}{2}=\boxed{49,5\,cm^2} \\ \\
A_{_{\Delta ABD} } = \frac{AB\times h}{2}= \frac{11\times 9}{2}=\frac{99}{2}=\boxed{49,5\,cm^2} \\ \\
A_{_{\Delta ADC} } = \frac{CD\times h}{2}= \frac{8\times 9}{2}=\frac{72}{2}=\boxed{36^2\,cm} \\ \\
A_{_{\Delta DCB} } = \frac{CD\times h}{2}= \frac{8\times 9}{2}=\frac{72}{2}=\boxed{36^2\,cm}[/tex]
