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Finding the Fourth Proportional to 428.47, 641.49 and 394.45

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Solution

The fourth proportional to 428.47, 641.49 and 394.45 is: 590.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.47 : 641.49 = 394.45 : x
  2. Step 2: Convert to fraction form
    428.47/641.49 = 394.45/x
  3. Step 3: Cross multiply
    428.47x = 641.49 × 394.45
  4. Step 4: Simplify right side
    428.47x = 253,035.73
  5. Step 5: Solve for x
    x = 253,035.73/428.47
  6. Step 6: Final answer
    x = 590.56

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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.