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Finding the Fourth Proportional to 128.92, 178.05 and 92.13

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Solution

The fourth proportional to 128.92, 178.05 and 92.13 is: 127.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.92 : 178.05 = 92.13 : x
  2. Step 2: Convert to fraction form
    128.92/178.05 = 92.13/x
  3. Step 3: Cross multiply
    128.92x = 178.05 × 92.13
  4. Step 4: Simplify right side
    128.92x = 16,403.75
  5. Step 5: Solve for x
    x = 16,403.75/128.92
  6. Step 6: Final answer
    x = 127.24

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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.