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Finding the Fourth Proportional to 638.67, 881.28 and 405.75

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Solution

The fourth proportional to 638.67, 881.28 and 405.75 is: 559.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.67 : 881.28 = 405.75 : x
  2. Step 2: Convert to fraction form
    638.67/881.28 = 405.75/x
  3. Step 3: Cross multiply
    638.67x = 881.28 × 405.75
  4. Step 4: Simplify right side
    638.67x = 357,579.36
  5. Step 5: Solve for x
    x = 357,579.36/638.67
  6. Step 6: Final answer
    x = 559.88

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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.