Question

evaluate (19.9)square by using Identity -2

Answer 1

Answer:

399.9

Step-by-step explanation:

Identity used: (a+b)² = a² + b² + 2ab

$(19.9)^2 = (20 - 0.1)^2 = (20^2 + 0.1^2 + 2(20)(0.1)) = (400 + 0.01 - 4) = \boxed{396.01}$

Hope it helps.

Answer 2

Answer:

396.01

Step-by-step explanation:

Given:- $(19.9)^{2}$

To Find:- Evaluate $(19.9)^{2}$ by using Identity II.

Solution:-

An Identity is known as an equality that holds true no matter what are the values chosen for its variables. They are used in rearranging or simplifying algebraic expressions.

As we know, Identity II = $(a+b)^{2} = a^{2} + b^{2} + 2ab$

So we can write $(19.9)^{2}$ as ( 19.9 )( 19.9 )

= ( 19.9 )( 19.9 )

= ( 19 + 0.9 )( 19 + 0.9 )

= 19 × 19 + 0.9 × 0.9 + 2 × 19 × 0.9

= 361 + 0.81 + 34.2

= 361.81 + 34.2

= 396.01

Therefore, after evaluating $(19.9)^{2}$ by using Identity II the value is 396.01

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