The boundary of the shaded region in the adjoining figure is - Sri Chaitanya Infinity Learn Best Online Courses for NCERT Solutions, CBSE, ICSE, JEE, NEET, Olympiad and Class 6 to 12

In the figure, there are three semicircles, where the diameter of one semicircle is 56 cm.
The radius of a semicircle is

r = 562 = 28 c m

.
The circumference of the semicircle is,

P 1 = 227 × 28 = 88 m m

.
Similarly, for a semi-circle which has diameter 28 cm, the radius is

r = 282 = 14 m m

P 2 = 227 × 14 = 44 m m

For the third semicircle, it is also 44 mm.
So, the boundary of the shaded region is,

88 + 44 + 44 = 176 m m

Hence, the correct option is 4.

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