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Finding the Fourth Proportional to 512.20, 768.30 and 281.80

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Solution

The fourth proportional to 512.20, 768.30 and 281.80 is: 422.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    512.20 : 768.30 = 281.80 : x
  2. Step 2: Convert to fraction form
    512.20/768.30 = 281.80/x
  3. Step 3: Cross multiply
    512.20x = 768.30 × 281.80
  4. Step 4: Simplify right side
    512.20x = 216,506.94
  5. Step 5: Solve for x
    x = 216,506.94/512.20
  6. Step 6: Final answer
    x = 422.70

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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.