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Finding the Fourth Proportional to 431.20, 645.90 and 339.46

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Solution

The fourth proportional to 431.20, 645.90 and 339.46 is: 508.48

Step by Step Solution

  1. Step 1: Write the proportion equation
    431.20 : 645.90 = 339.46 : x
  2. Step 2: Convert to fraction form
    431.20/645.90 = 339.46/x
  3. Step 3: Cross multiply
    431.20x = 645.90 × 339.46
  4. Step 4: Simplify right side
    431.20x = 219,257.21
  5. Step 5: Solve for x
    x = 219,257.21/431.20
  6. Step 6: Final answer
    x = 508.48

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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.