Question

Find the cube of (1.2).​

Answer 1

Answer:

cube of 1.2

1.2*1.2*1.2

1.728

Answer 2

cube of (1.2) is 1.728

Given:

• Cube of (1.2)

To Find:

• Value

Solution:

(a + b)³ = a³  + b³ + 3ab(a + b)

(a/b)³ = a³/b³

Step 1:

Rewrite 1.2 as  12/10

Step 3:

Use (a/b)³ = a³/b³   hence

(1.2)³ = (12/10)³ = 12³/10³

Step 3:

Evaluate 12³ using (a + b)³  where a= 10 and b = 2

(12)³ = (10+2)³  

= 10³ + 2³ + 3(10)(2)(10 + 2)

= 1000 + 8 + 60(12)

= 1000 + 8 + 720

= 1728

Step 4:  

Calculate 10³

10³ = 10 × 10 × 10 = 1000

Step 5:  

In (1.2)³  = 12³/10³  Substitute (12)³ = 1728 and 10³ =  1000

(1.2)³  = 1728/1000

=>  (1.2)³  = 1.728

Hence  cube of (1.2) is 1.728