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Finding the Fourth Proportional to 309.38, 423.28 and 308.09

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Solution

The fourth proportional to 309.38, 423.28 and 308.09 is: 421.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.38 : 423.28 = 308.09 : x
  2. Step 2: Convert to fraction form
    309.38/423.28 = 308.09/x
  3. Step 3: Cross multiply
    309.38x = 423.28 × 308.09
  4. Step 4: Simplify right side
    309.38x = 130,408.34
  5. Step 5: Solve for x
    x = 130,408.34/309.38
  6. Step 6: Final answer
    x = 421.52

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.