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Finding the Fourth Proportional to 627.28, 865.48 and 390.86

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Solution

The fourth proportional to 627.28, 865.48 and 390.86 is: 539.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    627.28 : 865.48 = 390.86 : x
  2. Step 2: Convert to fraction form
    627.28/865.48 = 390.86/x
  3. Step 3: Cross multiply
    627.28x = 865.48 × 390.86
  4. Step 4: Simplify right side
    627.28x = 338,281.51
  5. Step 5: Solve for x
    x = 338,281.51/627.28
  6. Step 6: Final answer
    x = 539.28

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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.