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Finding the Fourth Proportional to 71.92, 107.76 and 39.84

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Solution

The fourth proportional to 71.92, 107.76 and 39.84 is: 59.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.92 : 107.76 = 39.84 : x
  2. Step 2: Convert to fraction form
    71.92/107.76 = 39.84/x
  3. Step 3: Cross multiply
    71.92x = 107.76 × 39.84
  4. Step 4: Simplify right side
    71.92x = 4,293.16
  5. Step 5: Solve for x
    x = 4,293.16/71.92
  6. Step 6: Final answer
    x = 59.69

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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.