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Finding the Fourth Proportional to 698.31, 1,046.78 and 390.43

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Solution

The fourth proportional to 698.31, 1,046.78 and 390.43 is: 585.25

Step by Step Solution

  1. Step 1: Write the proportion equation
    698.31 : 1,046.78 = 390.43 : x
  2. Step 2: Convert to fraction form
    698.31/1,046.78 = 390.43/x
  3. Step 3: Cross multiply
    698.31x = 1,046.78 × 390.43
  4. Step 4: Simplify right side
    698.31x = 408,689.08
  5. Step 5: Solve for x
    x = 408,689.08/698.31
  6. Step 6: Final answer
    x = 585.25

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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.