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Finding the Fourth Proportional to 129.42, 178.61 and 76.97

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Solution

The fourth proportional to 129.42, 178.61 and 76.97 is: 106.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.42 : 178.61 = 76.97 : x
  2. Step 2: Convert to fraction form
    129.42/178.61 = 76.97/x
  3. Step 3: Cross multiply
    129.42x = 178.61 × 76.97
  4. Step 4: Simplify right side
    129.42x = 13,746.33
  5. Step 5: Solve for x
    x = 13,746.33/129.42
  6. Step 6: Final answer
    x = 106.21

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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.