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Finding the Fourth Proportional to 61.70, 85.05 and 39.83

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Solution

The fourth proportional to 61.70, 85.05 and 39.83 is: 54.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    61.70 : 85.05 = 39.83 : x
  2. Step 2: Convert to fraction form
    61.70/85.05 = 39.83/x
  3. Step 3: Cross multiply
    61.70x = 85.05 × 39.83
  4. Step 4: Simplify right side
    61.70x = 3,387.12
  5. Step 5: Solve for x
    x = 3,387.12/61.70
  6. Step 6: Final answer
    x = 54.90

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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.