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Finding the Fourth Proportional to 429.78, 644.94 and 213.38

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Solution

The fourth proportional to 429.78, 644.94 and 213.38 is: 320.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.78 : 644.94 = 213.38 : x
  2. Step 2: Convert to fraction form
    429.78/644.94 = 213.38/x
  3. Step 3: Cross multiply
    429.78x = 644.94 × 213.38
  4. Step 4: Simplify right side
    429.78x = 137,617.30
  5. Step 5: Solve for x
    x = 137,617.30/429.78
  6. Step 6: Final answer
    x = 320.20

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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.