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Finding the Fourth Proportional to 638.40, 881.14 and 405.48

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Solution

The fourth proportional to 638.40, 881.14 and 405.48 is: 559.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.40 : 881.14 = 405.48 : x
  2. Step 2: Convert to fraction form
    638.40/881.14 = 405.48/x
  3. Step 3: Cross multiply
    638.40x = 881.14 × 405.48
  4. Step 4: Simplify right side
    638.40x = 357,284.65
  5. Step 5: Solve for x
    x = 357,284.65/638.40
  6. Step 6: Final answer
    x = 559.66

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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.