hitunglah daerah yang diarsir!!

1. cari luas persegi
[tex]luas \: = {s}^{2} = {21}^{2} = 441 \: {cm}^{2} [/tex]
2. cari luas setengah lingkaran yang r = 14 cm
[tex]luas \: = \frac{1}{2} \times \pi \times {r}^{2} \\ = \frac{1}{2} \times \frac{22}{7} \times {14}^{2} \\ = \frac{11}{7} \times 196 \\ = 11 \times 28 = 308 \: {cm}^{2} [/tex]
3. cari luas lingkaran yang r = 7 cm
[tex]luas = \frac{1}{2} \times \pi \times {r}^{2} \\ = \frac{1}{2} \times \frac{22}{7} \times {7}^{2} = \frac{11}{7} \times 7 \times 7 \\ = 11 \times 7 = 77 \: { \: cm}^{2} [/tex]
4. luas arsiran
[tex]luas \: = 441 - 308 - 77 = 56 \: {cm}^{2} [/tex]