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Finding the Fourth Proportional to 429.20, 644.10 and 209.59

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Solution

The fourth proportional to 429.20, 644.10 and 209.59 is: 314.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.20 : 644.10 = 209.59 : x
  2. Step 2: Convert to fraction form
    429.20/644.10 = 209.59/x
  3. Step 3: Cross multiply
    429.20x = 644.10 × 209.59
  4. Step 4: Simplify right side
    429.20x = 134,995.70
  5. Step 5: Solve for x
    x = 134,995.70/429.20
  6. Step 6: Final answer
    x = 314.53

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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.