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Finding the Fourth Proportional to 679.38, 1,019.27 and 386.56

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Solution

The fourth proportional to 679.38, 1,019.27 and 386.56 is: 579.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    679.38 : 1,019.27 = 386.56 : x
  2. Step 2: Convert to fraction form
    679.38/1,019.27 = 386.56/x
  3. Step 3: Cross multiply
    679.38x = 1,019.27 × 386.56
  4. Step 4: Simplify right side
    679.38x = 394,009.01
  5. Step 5: Solve for x
    x = 394,009.01/679.38
  6. Step 6: Final answer
    x = 579.95

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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.