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Finding the Fourth Proportional to 512.34, 768.78 and 391.38

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Solution

The fourth proportional to 512.34, 768.78 and 391.38 is: 587.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    512.34 : 768.78 = 391.38 : x
  2. Step 2: Convert to fraction form
    512.34/768.78 = 391.38/x
  3. Step 3: Cross multiply
    512.34x = 768.78 × 391.38
  4. Step 4: Simplify right side
    512.34x = 300,885.12
  5. Step 5: Solve for x
    x = 300,885.12/512.34
  6. Step 6: Final answer
    x = 587.28

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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.