Question

Pragya wrapped a cord around a circular pipe of radius 4cm and cut off the lenght required of the cord. Then she wrapped it around a square bix of side 4cm. Did she have any cord left? (π = 3.14)

Answer 1

Answer:

⏺Solution: Given, Radius of pipe = 4cm, Side of square box = 4cm

Here, cord is wrapped around the circular pipe.

Therefore, length of cord = circumference of pipe

Circumference of circle `= 2πr`

`= 2 xx 3.14 xx 4= 6.28 xx 4 = 25.12` cm

Hence, 25.12 cm long wire is required to wrap around the circular pipe.

The same cord is wrapped around the square box.

The length of wire required = The perimeter of square

`= 4 xx \text(side) = 4 xx 4 = 16` cm

Hence, the length of cord left after wrapping over the square box

= Length of cord required to wrap around circular pipe — length required to wrap around the square box

= 25.12cm — 16cm = 9.12 cm

Answer 2

Solution-

Given- Radius of pipe = 4 cm

Side of square box = 4cm

Then,the cord is wrapped around a square box of side 4 cm

To find-The length of cord left after wrapping over the square box.

Solution-

Length of cord = Circumference of pipe

Circumference of circle =

$2\pi \: r$

$2 \times 3.14 \times 4 = 25.12 \: cm$

So,25.12 cm long wire is required to wrap around the circular pipe.

The length of wire required = The perimeter of square.

$4 \times 4 = 16 \: cm$

Therefore, length of cord left after wrapping over the square box=

Length of cord required to wrap around circular pipe — Length required to wrap around the square box

$25.12 - 16 = 9.12 \: cm$