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Finding the Fourth Proportional to 638.60, 881.27 and 389.87

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Solution

The fourth proportional to 638.60, 881.27 and 389.87 is: 538.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.60 : 881.27 = 389.87 : x
  2. Step 2: Convert to fraction form
    638.60/881.27 = 389.87/x
  3. Step 3: Cross multiply
    638.60x = 881.27 × 389.87
  4. Step 4: Simplify right side
    638.60x = 343,578.79
  5. Step 5: Solve for x
    x = 343,578.79/638.60
  6. Step 6: Final answer
    x = 538.02

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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.