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Finding the Fourth Proportional to 209.61, 289.08 and 135.90

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Solution

The fourth proportional to 209.61, 289.08 and 135.90 is: 187.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    209.61 : 289.08 = 135.90 : x
  2. Step 2: Convert to fraction form
    209.61/289.08 = 135.90/x
  3. Step 3: Cross multiply
    209.61x = 289.08 × 135.90
  4. Step 4: Simplify right side
    209.61x = 39,285.97
  5. Step 5: Solve for x
    x = 39,285.97/209.61
  6. Step 6: Final answer
    x = 187.42

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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.