A) \( \Large \frac{17.5}{2} \times \frac{3.5}{2}\ \pi\ cm^{2} \) |
B) \( \Large \frac{17.5 \times 21}{2}\ \pi\ cm^{2} \) |
C) \( \Large \frac{35 \times 21}{16}\ \pi\ cm^{2} \) |
D) \( \Large \frac{35 \times 21 \pi }{8}\ cm^{2} \) |
C) \( \Large \frac{35 \times 21}{16}\ \pi\ cm^{2} \) |
Required area = (Area of semi circle AC - Area of semi-circle AB) + (Area of semi-circle BE - Area of semi circle CD) + (Area of semi-circle DE)
= \( \Large \left[ \frac{1}{2} \pi \left(\frac{10.5}{2}\right)^{2}-\frac{1}{2} \pi \left(\frac{7}{2}\right)^{2} \right] \) \( \Large + \left[ \frac{1}{2} \pi \left(\frac{17.5}{2}\right)^{2} - \frac{1}{2} \pi \left(\frac{7}{2}\right)^{2} \right] + \frac{1}{2} \pi \left(\frac{7}{2}\right)^{2} \)
= \( \Large \frac{ \pi }{2}\left[ \left(\frac{10.5}{2}\right)^{2}+ \left(\frac{17.5}{2}\right)^{2}- \left(\frac{7}{2}\right)^{2} \right] \)
= \( \Large \frac{ \pi }{8}\left[ \left(10.5\right)^{2}+ \left(17.5\right)^{2}- \left(7\right)^{2} \right] \)
= \( \Large \frac{ \pi }{8}\left[ \left(10.5\right)^{2}+ \left(10.5\right) \left(24.5\right) \right] \)
= \( \Large \frac{ \pi }{8}\left[ \left(10.5\right) \left(35\right) \right] \)
= \( \Large \frac{ \pi }{16} \left(35\right) \left(21\right) cm^{2} \)