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Finding the Fourth Proportional to 309.43, 426.80 and 209.88

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Solution

The fourth proportional to 309.43, 426.80 and 209.88 is: 289.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.43 : 426.80 = 209.88 : x
  2. Step 2: Convert to fraction form
    309.43/426.80 = 209.88/x
  3. Step 3: Cross multiply
    309.43x = 426.80 × 209.88
  4. Step 4: Simplify right side
    309.43x = 89,577.31
  5. Step 5: Solve for x
    x = 89,577.31/309.43
  6. Step 6: Final answer
    x = 289.49

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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.