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Finding the Fourth Proportional to 129.22, 178.31 and 76.76

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Solution

The fourth proportional to 129.22, 178.31 and 76.76 is: 105.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.22 : 178.31 = 76.76 : x
  2. Step 2: Convert to fraction form
    129.22/178.31 = 76.76/x
  3. Step 3: Cross multiply
    129.22x = 178.31 × 76.76
  4. Step 4: Simplify right side
    129.22x = 13,687.08
  5. Step 5: Solve for x
    x = 13,687.08/129.22
  6. Step 6: Final answer
    x = 105.92

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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.