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Finding the Fourth Proportional to 278.98, 385.31 and 209.34

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Solution

The fourth proportional to 278.98, 385.31 and 209.34 is: 289.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    278.98 : 385.31 = 209.34 : x
  2. Step 2: Convert to fraction form
    278.98/385.31 = 209.34/x
  3. Step 3: Cross multiply
    278.98x = 385.31 × 209.34
  4. Step 4: Simplify right side
    278.98x = 80,661.32
  5. Step 5: Solve for x
    x = 80,661.32/278.98
  6. Step 6: Final answer
    x = 289.13

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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.