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Finding the Fourth Proportional to 129.05, 178.12 and 82.42

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Solution

The fourth proportional to 129.05, 178.12 and 82.42 is: 113.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.05 : 178.12 = 82.42 : x
  2. Step 2: Convert to fraction form
    129.05/178.12 = 82.42/x
  3. Step 3: Cross multiply
    129.05x = 178.12 × 82.42
  4. Step 4: Simplify right side
    129.05x = 14,680.31
  5. Step 5: Solve for x
    x = 14,680.31/129.05
  6. Step 6: Final answer
    x = 113.75

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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.