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Finding the Fourth Proportional to 217.12, 299.56 and 129.72

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Solution

The fourth proportional to 217.12, 299.56 and 129.72 is: 178.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    217.12 : 299.56 = 129.72 : x
  2. Step 2: Convert to fraction form
    217.12/299.56 = 129.72/x
  3. Step 3: Cross multiply
    217.12x = 299.56 × 129.72
  4. Step 4: Simplify right side
    217.12x = 38,858.92
  5. Step 5: Solve for x
    x = 38,858.92/217.12
  6. Step 6: Final answer
    x = 178.97

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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.