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Finding the Fourth Proportional to 129.21, 177.15 and 126.78

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Solution

The fourth proportional to 129.21, 177.15 and 126.78 is: 173.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.21 : 177.15 = 126.78 : x
  2. Step 2: Convert to fraction form
    129.21/177.15 = 126.78/x
  3. Step 3: Cross multiply
    129.21x = 177.15 × 126.78
  4. Step 4: Simplify right side
    129.21x = 22,459.08
  5. Step 5: Solve for x
    x = 22,459.08/129.21
  6. Step 6: Final answer
    x = 173.82

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.