Find the cubes of the following numbers:(i) 7(ii) 12(iii) 16(iv) 21(v)

1.	Find the cubes of the following numbers:(i) 7(ii) 12(iii) 16(iv) 21(v) 40(vi) 55(vii) 100(viii) 302(ix) 301
Answer» (i) 7 Cube of 7 = 7 × 7 × 7 = 343 (ii) 12 Cube of 12 = 12 × 12 × 12 = 1728 (iii) 16 Cube of 16 = 16 × 16 ×16 = 4096 (iv) 21 cube of 21 = 21 × 21 × 21 = 9261 (v) 40 Cube of 40 = 40 × 40 × 40 = 64000 (vi) 55 Cube of 55 = 55 × 55 × 55 = 166375 (vii) 100 Cube of 100 = 100 × 100 × 100 = 1000000 (viii) 302 To find cube of 302 we make it in form (a + b)³, Which make caluclation easier = (a + b) = a³ + b³ + 3a²b + 3ab² = (300 + 2)³ + 3x300² x 2 + 3x300x² = 27000000 + 8 + 540000 + 3600 = 27362408. (ix) 301 To find cube of 301 we make it in form (a + b)³, Which make calculation easier. = (a + b)³ = a³ + b³ + 3a²b + 3ab² = (300 + 1)³ = 300³ + 1³ + 3x300²x1 + 3x300x1³ = 27000000 + 1 + 270000 + 900 = 27180601.

Find the cubes of the following numbers:(i) 7(ii) 12(iii) 16(iv) 21(v) 40(vi) 55(vii) 100(viii) 302(ix) 301

Answer»

(i) 7

Cube of 7 = 7 × 7 × 7 = 343

(ii) 12

Cube of 12 = 12 × 12 × 12 = 1728

(iii) 16

Cube of 16 = 16 × 16 ×16 = 4096

(iv) 21

cube of 21 = 21 × 21 × 21 = 9261

(v) 40

Cube of 40 = 40 × 40 × 40 = 64000

(vi) 55

Cube of 55 = 55 × 55 × 55 = 166375

(vii) 100

Cube of 100 = 100 × 100 × 100 = 1000000

(viii) 302

To find cube of 302 we make it in form (a + b)³, Which make caluclation easier

= (a + b) = a³ + b³ + 3a²b + 3ab² = (300 + 2)³ + 3x300² x 2 + 3x300x²

= 27000000 + 8 + 540000 + 3600 = 27362408.

(ix) 301

To find cube of 301 we make it in form (a + b)³, Which make calculation easier.

= (a + b)³ = a³ + b³ + 3a²b + 3ab² = (300 + 1)³ = 300³ + 1³ + 3x300²x1 + 3x300x1³

= 27000000 + 1 + 270000 + 900 = 27180601.