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Finding the Fourth Proportional to 429.31, 644.16 and 209.81

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Solution

The fourth proportional to 429.31, 644.16 and 209.81 is: 314.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.31 : 644.16 = 209.81 : x
  2. Step 2: Convert to fraction form
    429.31/644.16 = 209.81/x
  3. Step 3: Cross multiply
    429.31x = 644.16 × 209.81
  4. Step 4: Simplify right side
    429.31x = 135,150.16
  5. Step 5: Solve for x
    x = 135,150.16/429.31
  6. Step 6: Final answer
    x = 314.81

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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.