Question

25 rings each of radius ,4/5 cm are placed inside a square of side 12 cm find the unoccupied area left in the square

Answer 1

Side of square = 12cm
Area of square = s × s
= 12 × 12 = 144 cm^2
Area of circle = pi r^2
r = 4/5 cm
Area of one ring = 314/100 × 4/5 × 4/5
Area of 25 rings = 25 × 314/100 × 4/5 × 4/5
= 62.8 cm^2
unoccupied area = 144 - 62.8
= 81.2cm^2

Hope it helps.

Answer 2

$hi...$
Radius of circular ring = 4/5 cm.

$area \: of \: ring = \pi {r}^{2}$
$= \frac{22}{7} \times ({ \frac{4}{5} )}^{2}$

$= \frac{22}{7} \times \frac{16}{25}$

$= \frac{352}{175}$

$= 2.01 {cm}^{2}$

Area of 25 rings = 25 × 2.01 = 50.25 sq.cm.

Side of square = 12 cm.

Area of square = side × side
Area of square = 12 × 12 = 144 sq .cm.

Thus ,
The area of square is 144 sq. cm

Area of unoccupied space left =
Area of square - Area of 25 rings
= 144 - 50.25
= 93.75 sq . cm
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Final Answer :
The unoccupied area left is 93 sq. cm.
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hope this helps ! ! !