Simplify the following expression:
(Correct your answer up to three decimal places)
- AOption (a)
1.414
- BOption (b)
2.314
- COption (c)
1.314
- DOption (d)
2.414
View answer & explanationHide answer & explanation
Correct answer
1.414
Why this answer is correct
Shortcut Trick
Equate decimal places: Total numerator places = 13, Total denominator places = 12, resulting in a factor of 10−1.
Identify powers: 6859 = 193, 54872 = 383 = (2 × 19)3, and 1156 = 342 = (2 × 17)2.
Simplify the ratios: (19/38)3 × (34/17)2 × (64000/1600) × 0.1 = (1/8) × 4 × 40 × 0.1 = 2.
Calculate the final root: √2 ≈ 1.414.
∴ The correct answer is 1.414.
Alternate Method
Given Expression: √( (0.6859 × 0.1156 × 0.64000) / (0.289 × 0.1600 × 0.54872) )
⇒ Count total decimal places in Numerator: 4 + 4 + 5 = 13.
⇒ Count total decimal places in Denominator: 3 + 4 + 5 = 12.
⇒ Remove decimals by adjusting powers of 10: √( (6859 × 1156 × 64000) / (289 × 1600 × 54872) × 10−1 )
⇒ Simplify the large numbers using prime factorization: 6859 = 193, 1156 = 342, 289 = 172, 54872 = 383.
⇒ √( (193 × 342 × 40) / (172 × 383 × 10) )
⇒ √( (193 × (2 × 17)2 × 40) / (172 × (2 × 19)3 × 10) )
⇒ √( (193 × 4 × 172 × 40) / (172 × 8 × 193 × 10) )
⇒ Cancel common terms: √( (4 × 40) / (8 × 10) ) = √(160 / 80) = √2
⇒ Square root of 2 up to three decimal places = 1.414
∴ The correct answer is 1.414.
Additional Information
Cubes of Numbers
Memorizing cubes up to 20 is crucial for simplification: 193 = 6859 and 383 = 54872.
Square Root Constants
Standard square root values frequently used in exams: √2 ≈ 1.414 and √3 ≈ 1.732.
Power and Indices Rule
For any numbers a and b: (a × b)n = an × bn. This helps in simplifying ratios like (34/17)2 = 22 = 4.