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Finding the Fourth Proportional to 679.45, 1,019.31 and 387.10

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Solution

The fourth proportional to 679.45, 1,019.31 and 387.10 is: 580.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    679.45 : 1,019.31 = 387.10 : x
  2. Step 2: Convert to fraction form
    679.45/1,019.31 = 387.10/x
  3. Step 3: Cross multiply
    679.45x = 1,019.31 × 387.10
  4. Step 4: Simplify right side
    679.45x = 394,574.90
  5. Step 5: Solve for x
    x = 394,574.90/679.45
  6. Step 6: Final answer
    x = 580.73

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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.