a) Avem dreptunghiurile :
ABCD, ABEF, AGIF, AGHD
BEIG, BCHG
CHIE, CDFE
DFIH.
Sunt, în total, 9 dreptunghiuri.
b) Cu notațiile din figură, avem:
[tex]\it \left.\begin{aligned} \dfrac{\mathcal{A}_{DQTP}}{\mathcal{A}_{QAMT}} =\dfrac{xz}{yz}=\dfrac{x}{y}\\ \\ \\ \dfrac{\mathcal{A}_{PTNC}}{\mathcal{A}_{TMBN}} =\dfrac{xt}{yt}=\dfrac{x}{y} \end{aligned} \right\} \Rightarrow \dfrac{\mathcal{A}_{DQTP}}{\mathcal{A}_{QAMT}} =\dfrac{\mathcal{A}_{PTNC}}{\mathcal{A}_{TMBN}} \Rightarrow \dfrac{16}{12}=\dfrac{\mathcal{A}_{PTNC}}{27} \Rightarrow\\ \\ \\ \Rightarrow \mathcal{A}_{PTNC} =\dfrac{\ 16\cdot27^{(3}}{12} =\dfrac{16\cdot9}{4} =36\ cm^2[/tex]
[tex]\it \mathcal{A}_{ABCD} = 16+12+27+36=91\ cm^2[/tex]
