Question

Using suitable identity, evaluate 10.1 × 10.2.

Answer 1

Answer:

$10.1 \times 10.2 \\ (x + a)(x + b) = x {}^{2} + (b + a)x + ab \\ x = 10 \: a = 0.1 \: \: b = 0.2 \\ (10 + 0.1)(10 + 0.2)$

$= 10 {}^{2} + (0.1 + 0.2)10 + 0.1 \times 0.2$

$= 100 + 3 + 0.02 \\ = 103.02$

Answer 2

The value of $10.1\times 10.2=103.02$

Step-by-step explanation:

We have,

$10.1\times 10.2$

To find, the value of $10.1\times 10.2=?$

∴ $10.1\times 10.2$

$=(10+0.1)(10+0.2)$

Using the identity,

$(x+a)(x+b)=x^{2}+(a+b)x+ab$

Here, x = 10, a = 0.1 and b = 0.2

$(10+0.1)(10+0.2)=10^{2}+(0.1+0.2)10+(0.1)(0.2)$

$=100+(0.3)10+0.02$

$=100+3+0.02$

= 103 + 0.02

= 103.02

Hence, the value of $10.1\times 10.2=103.02$