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Finding the Fourth Proportional to 418.40, 627.70 and 129.81

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Solution

The fourth proportional to 418.40, 627.70 and 129.81 is: 194.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    418.40 : 627.70 = 129.81 : x
  2. Step 2: Convert to fraction form
    418.40/627.70 = 129.81/x
  3. Step 3: Cross multiply
    418.40x = 627.70 × 129.81
  4. Step 4: Simplify right side
    418.40x = 81,481.74
  5. Step 5: Solve for x
    x = 81,481.74/418.40
  6. Step 6: Final answer
    x = 194.75

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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.