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Finding the Fourth Proportional to 611.45, 916.11 and 428.49

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Solution

The fourth proportional to 611.45, 916.11 and 428.49 is: 641.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    611.45 : 916.11 = 428.49 : x
  2. Step 2: Convert to fraction form
    611.45/916.11 = 428.49/x
  3. Step 3: Cross multiply
    611.45x = 916.11 × 428.49
  4. Step 4: Simplify right side
    611.45x = 392,543.97
  5. Step 5: Solve for x
    x = 392,543.97/611.45
  6. Step 6: Final answer
    x = 641.99

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Double scale
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Similar ratio
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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.