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Finding the Fourth Proportional to 61.38, 84.70 and 39.55

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Solution

The fourth proportional to 61.38, 84.70 and 39.55 is: 54.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    61.38 : 84.70 = 39.55 : x
  2. Step 2: Convert to fraction form
    61.38/84.70 = 39.55/x
  3. Step 3: Cross multiply
    61.38x = 84.70 × 39.55
  4. Step 4: Simplify right side
    61.38x = 3,349.46
  5. Step 5: Solve for x
    x = 3,349.46/61.38
  6. Step 6: Final answer
    x = 54.57

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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.