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Finding the Fourth Proportional to 129.70, 178.91 and 76.55

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Solution

The fourth proportional to 129.70, 178.91 and 76.55 is: 105.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.70 : 178.91 = 76.55 : x
  2. Step 2: Convert to fraction form
    129.70/178.91 = 76.55/x
  3. Step 3: Cross multiply
    129.70x = 178.91 × 76.55
  4. Step 4: Simplify right side
    129.70x = 13,694.57
  5. Step 5: Solve for x
    x = 13,694.57/129.70
  6. Step 6: Final answer
    x = 105.59

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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.