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Finding the Fourth Proportional to 129.31, 178.40 and 79.54

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Solution

The fourth proportional to 129.31, 178.40 and 79.54 is: 109.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.31 : 178.40 = 79.54 : x
  2. Step 2: Convert to fraction form
    129.31/178.40 = 79.54/x
  3. Step 3: Cross multiply
    129.31x = 178.40 × 79.54
  4. Step 4: Simplify right side
    129.31x = 14,189.69
  5. Step 5: Solve for x
    x = 14,189.69/129.31
  6. Step 6: Final answer
    x = 109.74

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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.