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Finding the Fourth Proportional to 513.25, 768.15 and 390.80

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Solution

The fourth proportional to 513.25, 768.15 and 390.80 is: 584.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    513.25 : 768.15 = 390.80 : x
  2. Step 2: Convert to fraction form
    513.25/768.15 = 390.80/x
  3. Step 3: Cross multiply
    513.25x = 768.15 × 390.80
  4. Step 4: Simplify right side
    513.25x = 300,194.94
  5. Step 5: Solve for x
    x = 300,194.94/513.25
  6. Step 6: Final answer
    x = 584.89

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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.