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Finding the Fourth Proportional to 61.74, 85.18 and 39.92

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Solution

The fourth proportional to 61.74, 85.18 and 39.92 is: 55.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    61.74 : 85.18 = 39.92 : x
  2. Step 2: Convert to fraction form
    61.74/85.18 = 39.92/x
  3. Step 3: Cross multiply
    61.74x = 85.18 × 39.92
  4. Step 4: Simplify right side
    61.74x = 3,400.07
  5. Step 5: Solve for x
    x = 3,400.07/61.74
  6. Step 6: Final answer
    x = 55.08

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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.