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Finding the Fourth Proportional to 408.31, 563.69 and 390.89

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Solution

The fourth proportional to 408.31, 563.69 and 390.89 is: 539.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    408.31 : 563.69 = 390.89 : x
  2. Step 2: Convert to fraction form
    408.31/563.69 = 390.89/x
  3. Step 3: Cross multiply
    408.31x = 563.69 × 390.89
  4. Step 4: Simplify right side
    408.31x = 220,343.17
  5. Step 5: Solve for x
    x = 220,343.17/408.31
  6. Step 6: Final answer
    x = 539.65

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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.