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Finding the Fourth Proportional to 129.47, 193.86 and 121.78

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Solution

The fourth proportional to 129.47, 193.86 and 121.78 is: 182.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.47 : 193.86 = 121.78 : x
  2. Step 2: Convert to fraction form
    129.47/193.86 = 121.78/x
  3. Step 3: Cross multiply
    129.47x = 193.86 × 121.78
  4. Step 4: Simplify right side
    129.47x = 23,606.69
  5. Step 5: Solve for x
    x = 23,606.69/129.47
  6. Step 6: Final answer
    x = 182.33

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.