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Finding the Fourth Proportional to 627.30, 865.57 and 391.21

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Solution

The fourth proportional to 627.30, 865.57 and 391.21 is: 539.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    627.30 : 865.57 = 391.21 : x
  2. Step 2: Convert to fraction form
    627.30/865.57 = 391.21/x
  3. Step 3: Cross multiply
    627.30x = 865.57 × 391.21
  4. Step 4: Simplify right side
    627.30x = 338,613.36
  5. Step 5: Solve for x
    x = 338,613.36/627.30
  6. Step 6: Final answer
    x = 539.80

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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.