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Finding the Fourth Proportional to 644.68, 890.22 and 409

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Solution

The fourth proportional to 644.68, 890.22 and 409 is: 564.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    644.68 : 890.22 = 409 : x
  2. Step 2: Convert to fraction form
    644.68/890.22 = 409/x
  3. Step 3: Cross multiply
    644.68x = 890.22 × 409
  4. Step 4: Simplify right side
    644.68x = 364,099.98
  5. Step 5: Solve for x
    x = 364,099.98/644.68
  6. Step 6: Final answer
    x = 564.78

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.