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Finding the Fourth Proportional to 129.41, 178.55 and 80.31

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Solution

The fourth proportional to 129.41, 178.55 and 80.31 is: 110.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.41 : 178.55 = 80.31 : x
  2. Step 2: Convert to fraction form
    129.41/178.55 = 80.31/x
  3. Step 3: Cross multiply
    129.41x = 178.55 × 80.31
  4. Step 4: Simplify right side
    129.41x = 14,339.37
  5. Step 5: Solve for x
    x = 14,339.37/129.41
  6. Step 6: Final answer
    x = 110.80

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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.