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Finding the Fourth Proportional to 206.88, 285.36 and 129.12

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Solution

The fourth proportional to 206.88, 285.36 and 129.12 is: 178.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    206.88 : 285.36 = 129.12 : x
  2. Step 2: Convert to fraction form
    206.88/285.36 = 129.12/x
  3. Step 3: Cross multiply
    206.88x = 285.36 × 129.12
  4. Step 4: Simplify right side
    206.88x = 36,845.68
  5. Step 5: Solve for x
    x = 36,845.68/206.88
  6. Step 6: Final answer
    x = 178.10

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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.