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Finding the Fourth Proportional to 638.69, 881.37 and 389.92

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Solution

The fourth proportional to 638.69, 881.37 and 389.92 is: 538.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    638.69 : 881.37 = 389.92 : x
  2. Step 2: Convert to fraction form
    638.69/881.37 = 389.92/x
  3. Step 3: Cross multiply
    638.69x = 881.37 × 389.92
  4. Step 4: Simplify right side
    638.69x = 343,663.79
  5. Step 5: Solve for x
    x = 343,663.79/638.69
  6. Step 6: Final answer
    x = 538.08

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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.