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Finding the Fourth Proportional to 129.38, 178.46 and 76.88

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Solution

The fourth proportional to 129.38, 178.46 and 76.88 is: 106.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.38 : 178.46 = 76.88 : x
  2. Step 2: Convert to fraction form
    129.38/178.46 = 76.88/x
  3. Step 3: Cross multiply
    129.38x = 178.46 × 76.88
  4. Step 4: Simplify right side
    129.38x = 13,720.07
  5. Step 5: Solve for x
    x = 13,720.07/129.38
  6. Step 6: Final answer
    x = 106.05

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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.