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Finding the Fourth Proportional to 428.09, 641.30 and 319.97

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Solution

The fourth proportional to 428.09, 641.30 and 319.97 is: 479.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.09 : 641.30 = 319.97 : x
  2. Step 2: Convert to fraction form
    428.09/641.30 = 319.97/x
  3. Step 3: Cross multiply
    428.09x = 641.30 × 319.97
  4. Step 4: Simplify right side
    428.09x = 205,195.16
  5. Step 5: Solve for x
    x = 205,195.16/428.09
  6. Step 6: Final answer
    x = 479.33

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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.