If a wire is bent into the shape of a square, the area of

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If a wire is bent into the shape of a square, the area of the square is 81 sq. cm. When the wire is bent into a semicircular shape, the area of the semicircle (taking π = 22/7 ) is :

1. 154 cm²
2. 77 cm²
3. 44 cm²
4. 22 cm²

Correct Option: B

Using Rule 10,
The length of wire
= perimeter of the square
= 4 × √Area of square
= 4 × √81
= 4 × 9 = 36 cm
Now, perimeter of semicircular shape = 36 cm
⇒ (π × r + 2r) = 36 cm.

⇒ r		22	+ 2		²	= 36 cm
		7

⇒ r ×	36	= 36
	7

⇒ r ×	36 × 7	= 7 cm
	7

∴ Required area =	πr²	=	22 × 7 × 7	= 77 cm²
	2		7 × 2