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Finding the Fourth Proportional to 129.54, 178.76 and 77.09

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Solution

The fourth proportional to 129.54, 178.76 and 77.09 is: 106.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.54 : 178.76 = 77.09 : x
  2. Step 2: Convert to fraction form
    129.54/178.76 = 77.09/x
  3. Step 3: Cross multiply
    129.54x = 178.76 × 77.09
  4. Step 4: Simplify right side
    129.54x = 13,779.33
  5. Step 5: Solve for x
    x = 13,779.33/129.54
  6. Step 6: Final answer
    x = 106.37

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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.