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Finding the Fourth Proportional to 644.20, 889.04 and 392.31

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Solution

The fourth proportional to 644.20, 889.04 and 392.31 is: 541.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    644.20 : 889.04 = 392.31 : x
  2. Step 2: Convert to fraction form
    644.20/889.04 = 392.31/x
  3. Step 3: Cross multiply
    644.20x = 889.04 × 392.31
  4. Step 4: Simplify right side
    644.20x = 348,774.86
  5. Step 5: Solve for x
    x = 348,774.86/644.20
  6. Step 6: Final answer
    x = 541.41

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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.