Tolong bantu yang nomor 17 beserta cara

[tex] \frac{1}{2} \times {4}^{2} - 2(\frac{1}{2} \times {4}^{2} - \frac{1}{8} \times \pi \times {4}^{2} ) = \\ 8 - 2(8 - 2\pi) = 8 - 16 + 4\pi = (4\pi - 8) \: {cm}^{2} [/tex]