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Finding the Fourth Proportional to 309.29, 426.51 and 209.78

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Solution

The fourth proportional to 309.29, 426.51 and 209.78 is: 289.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.29 : 426.51 = 209.78 : x
  2. Step 2: Convert to fraction form
    309.29/426.51 = 209.78/x
  3. Step 3: Cross multiply
    309.29x = 426.51 × 209.78
  4. Step 4: Simplify right side
    309.29x = 89,473.27
  5. Step 5: Solve for x
    x = 89,473.27/309.29
  6. Step 6: Final answer
    x = 289.29

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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.