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Finding the Fourth Proportional to 512.98, 768.90 and 390.85

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Solution

The fourth proportional to 512.98, 768.90 and 390.85 is: 585.84

Step by Step Solution

  1. Step 1: Write the proportion equation
    512.98 : 768.90 = 390.85 : x
  2. Step 2: Convert to fraction form
    512.98/768.90 = 390.85/x
  3. Step 3: Cross multiply
    512.98x = 768.90 × 390.85
  4. Step 4: Simplify right side
    512.98x = 300,524.57
  5. Step 5: Solve for x
    x = 300,524.57/512.98
  6. Step 6: Final answer
    x = 585.84

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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.