question_answer 1)

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

Answer:

                Radius of the circular pipe (r) = 4 cm \[\therefore \]                  Circumference of the circular pipe \[\text{= 2 }\!\!\pi\!\!\text{ r = 2  }\!\!\times\!\!\text{  3}\text{.14  }\!\!\times\!\!\text{  4cm = 25}\text{.12 cm}\]     Perimeter of the square box of the side \[\text{4 cm = 4  }\!\!\times\!\!\text{  side = 4}\times \text{4 cm = 16 cm}\] \[\because \]     \[\text{25}\text{.12 cm  16 cm}\] \[\therefore \] She had extra cord left and the cord left \[=(25.12-16\text{) cm = 9}\text{.12 cm}\]