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Finding the Fourth Proportional to 208.20, 287.19 and 129.54

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Solution

The fourth proportional to 208.20, 287.19 and 129.54 is: 178.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    208.20 : 287.19 = 129.54 : x
  2. Step 2: Convert to fraction form
    208.20/287.19 = 129.54/x
  3. Step 3: Cross multiply
    208.20x = 287.19 × 129.54
  4. Step 4: Simplify right side
    208.20x = 37,202.59
  5. Step 5: Solve for x
    x = 37,202.59/208.20
  6. Step 6: Final answer
    x = 178.69

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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.