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Finding the Fourth Proportional to 426.34, 638.91 and 220.40

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Solution

The fourth proportional to 426.34, 638.91 and 220.40 is: 330.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    426.34 : 638.91 = 220.40 : x
  2. Step 2: Convert to fraction form
    426.34/638.91 = 220.40/x
  3. Step 3: Cross multiply
    426.34x = 638.91 × 220.40
  4. Step 4: Simplify right side
    426.34x = 140,812.57
  5. Step 5: Solve for x
    x = 140,812.57/426.34
  6. Step 6: Final answer
    x = 330.28

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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.