Question Details

A copper wire, when bent in the form of a square of encloses a region having 1089 sq cm. If the same wire is bent in the form of a circle, then find the area of the region enclosed by the wire.

Options

A

1332

B

1335

C

1338

D

1386

E

1380

Show Answer

Correct Answer :

Option D

1386

Solution :

The correct answer is 1386.

Let's solve the problem step-by-step by finding the length of the wire and then calculating the area of the circle formed by it.

Step 1: Find the side length of the square.
Let s be the side length of the square.
The area of a square is given by the formula:
Area of square=s2
We are given that the area of the square is 1089 sq cm. Therefore:
s2=1089
Taking the square root on both sides:
s=1089=33 cm

Step 2: Find the length of the wire (perimeter of the square).
The total length of the wire is equal to the perimeter of the square.
Perimeter of square=4·s
Length of wire=4·33=132 cm

Step 3: Find the radius of the circle.
If the same wire is bent to form a circle, the circumference of the circle will be equal to the length of the wire.
Let r be the radius of the circle. The formula for the circumference of a circle is:
Circumference=2·π·r
Setting this equal to the length of the wire (132 cm) and using π227:
2·227·r=132
447·r=132
Multiplying both sides by 744:
r=132·744
Since 132/44=3:
r=3·7=21 cm

Step 4: Calculate the area of the circle.
The area of a circle is given by the formula:
Area of circle=π·r2
Substituting r=21 cm and π=227:
Area=227·212
Area=227·21·21
Area=22·3·21
Area=66·21=1386 sq cm

Thus, the area of the region enclosed by the wire when bent into a circle is 1386 sq cm.

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