Question

The iron cube of side 42 com has a hole of diameter 14cm

Answer 1

Answer:

Step-by-step explanation:

Total surface of the cube = 6a²

                                          = 6 * 42 * 42

                                          = 10584 cm²

Hole that is drilled out, will make a cylinder shape in the middle of the cube

Volume  of iron in the cube = Volume of cube  - volume of cylinder

Volume of cube = a³

                          = 42 * 42 * 42

                         = 74088 cm³

Cylinder:

r = 14/2 = 7 cm

h = sideof the cube = 42 cm

Volume = πr²h

            $=\frac{22}{7}*7*7*42\\\\=22*7*7*6$

           = 6468 cm³

Volume  of iron in the cube = Volume of cube  - volume of cylinder

                                             = 74088 - 6468

                                             = 67620 cm³