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Finding the Fourth Proportional to 638.54, 881.21 and 389.80

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Solution

The fourth proportional to 638.54, 881.21 and 389.80 is: 537.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.54 : 881.21 = 389.80 : x
  2. Step 2: Convert to fraction form
    638.54/881.21 = 389.80/x
  3. Step 3: Cross multiply
    638.54x = 881.21 × 389.80
  4. Step 4: Simplify right side
    638.54x = 343,495.66
  5. Step 5: Solve for x
    x = 343,495.66/638.54
  6. Step 6: Final answer
    x = 537.94

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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.