Options:
A) $ 7cm^{2} $
B) $ 28cm^{2} $
C) $ 14cm^{2} $
D) $ 21cm^{2} $
Show Answer
Answer:
Correct Answer: B
Solution:
- (b)
We have, two sectors BCD and ABD.
Both are symmetrical.
Area of shaded portion = Area of sector BCD $ - $ Area of $ \Delta BCD $
$ =\frac{\pi r^{2}\theta }{360{}^\circ }-\frac{1}{2}\times b\times h $
$ =\frac{\pi {{(7)}^{2}}\times 90{}^\circ }{360{}^\circ }-\frac{1}{2}\times 7\times 7 $
$ =\frac{77}{2}-\frac{49}{2}=28/2sqcm $
$ \therefore $ Area of complete shaded region
$ =2\times \frac{28}{2}=28cm^{2} $