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Finding the Fourth Proportional to 85.92, 129.24 and 67.92

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Solution

The fourth proportional to 85.92, 129.24 and 67.92 is: 102.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.92 : 129.24 = 67.92 : x
  2. Step 2: Convert to fraction form
    85.92/129.24 = 67.92/x
  3. Step 3: Cross multiply
    85.92x = 129.24 × 67.92
  4. Step 4: Simplify right side
    85.92x = 8,777.98
  5. Step 5: Solve for x
    x = 8,777.98/85.92
  6. Step 6: Final answer
    x = 102.16

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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.