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Finding the Fourth Proportional to 309.45, 427.12 and 209.82

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Solution

The fourth proportional to 309.45, 427.12 and 209.82 is: 289.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    309.45 : 427.12 = 209.82 : x
  2. Step 2: Convert to fraction form
    309.45/427.12 = 209.82/x
  3. Step 3: Cross multiply
    309.45x = 427.12 × 209.82
  4. Step 4: Simplify right side
    309.45x = 89,620.58
  5. Step 5: Solve for x
    x = 89,620.58/309.45
  6. Step 6: Final answer
    x = 289.61

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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.