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Finding the Fourth Proportional to 638.76, 881.76 and 405.88

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Solution

The fourth proportional to 638.76, 881.76 and 405.88 is: 560.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.76 : 881.76 = 405.88 : x
  2. Step 2: Convert to fraction form
    638.76/881.76 = 405.88/x
  3. Step 3: Cross multiply
    638.76x = 881.76 × 405.88
  4. Step 4: Simplify right side
    638.76x = 357,888.75
  5. Step 5: Solve for x
    x = 357,888.75/638.76
  6. Step 6: Final answer
    x = 560.29

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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.