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Finding the Fourth Proportional to 664.31, 916.85 and 428.60

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Solution

The fourth proportional to 664.31, 916.85 and 428.60 is: 591.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    664.31 : 916.85 = 428.60 : x
  2. Step 2: Convert to fraction form
    664.31/916.85 = 428.60/x
  3. Step 3: Cross multiply
    664.31x = 916.85 × 428.60
  4. Step 4: Simplify right side
    664.31x = 392,965.27
  5. Step 5: Solve for x
    x = 392,965.27/664.31
  6. Step 6: Final answer
    x = 591.54

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.