Question

Pragya wrapped a cord around a circular pipe of radius $$4$$cm(adjoining figure) and cut off the length required of the cost. Then she wrapped it around a square box of side $$4$$cm(also shown). Did she have any cord left?(Take $$\pi =3.14$$)

Answer 1

Radius of pipe$$=4$$cm
Wrapping cord around circular pipe$$=2\pi r$$
$$=2\times 3.14\times 4=25.12$$cm
Again, wrapping cord around a square$$=4\times$$side
$$=4\times 4=16$$cm
Remaining cord$$=$$Cord wrapped on pipe$$-$$Cord wrapped on square $$=25.12-16=9.12$$cm
Thus, she has left $$9.12$$cm cord.