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Finding the Fourth Proportional to 309.20, 426.20 and 210.78

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Solution

The fourth proportional to 309.20, 426.20 and 210.78 is: 290.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.20 : 426.20 = 210.78 : x
  2. Step 2: Convert to fraction form
    309.20/426.20 = 210.78/x
  3. Step 3: Cross multiply
    309.20x = 426.20 × 210.78
  4. Step 4: Simplify right side
    309.20x = 89,833.38
  5. Step 5: Solve for x
    x = 89,833.38/309.20
  6. Step 6: Final answer
    x = 290.54

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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.