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Finding the Fourth Proportional to 309.20, 426.56 and 215.79

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Solution

The fourth proportional to 309.20, 426.56 and 215.79 is: 297.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.20 : 426.56 = 215.79 : x
  2. Step 2: Convert to fraction form
    309.20/426.56 = 215.79/x
  3. Step 3: Cross multiply
    309.20x = 426.56 × 215.79
  4. Step 4: Simplify right side
    309.20x = 92,046.30
  5. Step 5: Solve for x
    x = 92,046.30/309.20
  6. Step 6: Final answer
    x = 297.70

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.