Recognize uniform decimal scaling in sums of squares: Compute [(0.05)^2 + (0.41)^2 + (0.073)^2] / [(0.005)^2 + (0.041)^2 + (0.0073)^2] using powers-of-10 relationships.
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A0.1
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B10
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C100
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D1000
Answer
Correct Answer: 100
Explanation
Introduction / Context:This problem checks whether you can see patterns in decimal scaling. The denominator terms are each precisely one-tenth of the corresponding numerator terms, and squaring magnifies that scaling in a predictable way. Exploiting this pattern yields the answer instantly.
Given Data / Assumptions:
- Numerator: (0.05)^2 + (0.41)^2 + (0.073)^2.
- Denominator: (0.005)^2 + (0.041)^2 + (0.0073)^2.
Concept / Approach:If x is scaled to x/10, then (x/10)^2 = x^2/100. Since every denominator term is the square of a numerator term divided by 10, each denominator square equals the corresponding numerator square divided by 100. Thus the whole denominator is 1/100 of the numerator sum, and the ratio is 100.
Step-by-Step Solution:
Observe: 0.005 = 0.05/10; 0.041 = 0.41/10; 0.0073 = 0.073/10.Therefore: (0.005)^2 = (0.05)^2/100, etc.Sum of denominator squares = (sum of numerator squares)/100.Hence overall ratio = (Numerator) / (Numerator/100) = 100.Verification / Alternative check:
Pick one pair to test: (0.05)^2 = 0.0025; (0.005)^2 = 0.000025; indeed a factor of 1/100.Why Other Options Are Wrong:
- 0.1, 10, 1000: Each assumes an incorrect scaling factor (1/10, 10, or 1000) rather than 100.
Common Pitfalls:
- Forgetting that the square of a tenth is a hundredth.
- Adding before recognizing the uniform scaling wastes time and risks arithmetic slips.
Final Answer:
100