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Finding the Fourth Proportional to 925.39, 1,389 and 438.78

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Solution

The fourth proportional to 925.39, 1,389 and 438.78 is: 658.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    925.39 : 1,389 = 438.78 : x
  2. Step 2: Convert to fraction form
    925.39/1,389 = 438.78/x
  3. Step 3: Cross multiply
    925.39x = 1,389 × 438.78
  4. Step 4: Simplify right side
    925.39x = 609,465.42
  5. Step 5: Solve for x
    x = 609,465.42/925.39
  6. Step 6: Final answer
    x = 658.60

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.