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Finding the Fourth Proportional to 309.50, 464.31 and 138.50

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Solution

The fourth proportional to 309.50, 464.31 and 138.50 is: 207.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.50 : 464.31 = 138.50 : x
  2. Step 2: Convert to fraction form
    309.50/464.31 = 138.50/x
  3. Step 3: Cross multiply
    309.50x = 464.31 × 138.50
  4. Step 4: Simplify right side
    309.50x = 64,306.94
  5. Step 5: Solve for x
    x = 64,306.94/309.50
  6. Step 6: Final answer
    x = 207.78

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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.