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Finding the Fourth Proportional to 309.15, 426.70 and 209.59

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Solution

The fourth proportional to 309.15, 426.70 and 209.59 is: 289.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.15 : 426.70 = 209.59 : x
  2. Step 2: Convert to fraction form
    309.15/426.70 = 209.59/x
  3. Step 3: Cross multiply
    309.15x = 426.70 × 209.59
  4. Step 4: Simplify right side
    309.15x = 89,431.25
  5. Step 5: Solve for x
    x = 89,431.25/309.15
  6. Step 6: Final answer
    x = 289.28

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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.