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Finding the Fourth Proportional to 129.43, 178.64 and 115.75

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Solution

The fourth proportional to 129.43, 178.64 and 115.75 is: 159.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.43 : 178.64 = 115.75 : x
  2. Step 2: Convert to fraction form
    129.43/178.64 = 115.75/x
  3. Step 3: Cross multiply
    129.43x = 178.64 × 115.75
  4. Step 4: Simplify right side
    129.43x = 20,677.58
  5. Step 5: Solve for x
    x = 20,677.58/129.43
  6. Step 6: Final answer
    x = 159.76

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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.