Cube

Cube We know that the word ‘CUBE’ is used in geometry. A cube is a solid figure which has all its sides are equal. If the side of a cube in the adjoining figure is “a” units, then its volume is given by a x a x a = a3 cubic units. Here a3 is called “a cubed” or “a raised to the power three” or “a to the power 3”.

What are cube numbers? A cube number is a number that is the product of three numbers which are the same This diagram makes this concept clearer:

5 x 5 x 5 -5 x -5 x -5 25 x 5 25 x -5 125 -125 We know that - x - = + You can also have negative cube numbers Have a look at this: When we cube 5 we get 125 5 x 5 x 5 25 x 5 125 When we cube -5 we get -125 -5 x -5 x -5 25 x -5 -125 We know that - x - = + We know that + x - = - Note : When an negative number is multiplied by itself an even number of times, the product is positive When an negative number is multiplied by itself an odd number of times, the product is negative

Cube Numbers upto 15 (to be by hearted) 11 1331 2 8 12 1728 3 27 13 2197 4 64 14 2744 5 125 15 3375 6 216 16 4096 7 343 17 4913 8 512 18 5832 9 729 19 6859 10 1000 20 8000

Try These Find the value of the following (i) 43 (ii) (-9)3 (iii)