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Finding the Fourth Proportional to 817.20, 1,226.10 and 426.78

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Solution

The fourth proportional to 817.20, 1,226.10 and 426.78 is: 640.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    817.20 : 1,226.10 = 426.78 : x
  2. Step 2: Convert to fraction form
    817.20/1,226.10 = 426.78/x
  3. Step 3: Cross multiply
    817.20x = 1,226.10 × 426.78
  4. Step 4: Simplify right side
    817.20x = 523,274.96
  5. Step 5: Solve for x
    x = 523,274.96/817.20
  6. Step 6: Final answer
    x = 640.33

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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.