Question

b) Rohit makes a cuboid of dimensions 5 cm, 2 cm, and 5 cm using clay. How many
such cuboids will he need, to make a perfect cube.​

Answer 1

Answer:

FIRST WAY -

She has a Cuboid of volume 50cm cube.

Hence, the cube formed by these cuboids must be a multiple of 50.

THE FIRST CUBE THAT IS DIVISIBLE BY 50 IS 1000.

HENCE, number of cuboids required to form a cube is equal to 1000/50 = 20.

THEREFORE, THE ANSWER IS 20.

SECOND WAY -

L.C.M. of 5 and 2 gives the dimension of the cube to be formed.

L.C.M. of 5 and 2 is 10.

$VOL = 50cm^{3}$

Volume of bigger cube = 10³= 1000

Number of cuboids required to make the bigger cube = (Volume of a cuboid)/(Volume of cube)

= 1000/50

=20