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Finding the Fourth Proportional to 129.34, 178.37 and 85.70

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Solution

The fourth proportional to 129.34, 178.37 and 85.70 is: 118.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.34 : 178.37 = 85.70 : x
  2. Step 2: Convert to fraction form
    129.34/178.37 = 85.70/x
  3. Step 3: Cross multiply
    129.34x = 178.37 × 85.70
  4. Step 4: Simplify right side
    129.34x = 15,286.31
  5. Step 5: Solve for x
    x = 15,286.31/129.34
  6. Step 6: Final answer
    x = 118.19

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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.