tolong bantuin ya,,, no. 7 dan 8,,,pakai caranya,,, makasih

[tex]7.luas \: arsiran = luas \: persegi - luas \: lingkaran \\ = (s \times s) - (\pi {r}^{2} ) \\ = (14 \times 14) - ( \frac{22}{7} \times {7}^{2} ) \\ = 196 - 22 \times 7 \\ = 196 - 154 \\ = 42 {cm}^{2} \\8.luas \: arsiran = l \: lingk. \: besar - kecil \\ = \pi {r}^{2} - \pi {r}^{2} \\ = (\frac{22}{7} \times {28}^{2}) - (\frac{22}{7} \times {14}^{2} ) \\ = (22 \times 4 \times 28) - (22 \times 2 \times 14) \\ = 2464 - 616 \\ = 1848 {cm}^{2} \\ [/tex]
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