Evaluate: (9.9)²

Solution:

Given, (9.9)² = (10 - 0.1)²

Using standard identity: (a - b)² = a² - 2ab + b²

Here, a = 10 and b = 0.1

(9.9)² = (10 - 0.1)²

= (10)² - 2 (10)(0.1) + (0.1)²

= 100 - 2 + 0.01 = 98.01

✦ Try This: Evaluate: (8.8)²

Given, (8.8)² = (10 - 1.2)²

Using standard identity: (a - b)² = a² - 2ab + b²

(8.8)² = (10 - 1.2)²

= (10)² - 2 (10)(1.2) + (1.2)²

= 100 - 24 + 1.44 = 77.44

☛ Also Check: NCERT Solutions for Class 8 Maths Chapter 9

NCERT Exemplar Class 8 Maths Chapter 7 Problem 86(xiii)

Evaluate: (9.9)²

Summary:

Evaluating (9.9)² we get, 98.01

☛ Related Questions:

• Evaluate: 9.8 × 10.2
• Evaluate: 10.1 × 10.2
• Evaluate: (35.4)² - (14.6)²