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Finding the Fourth Proportional to 129.40, 193.85 and 105.28

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Solution

The fourth proportional to 129.40, 193.85 and 105.28 is: 157.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.40 : 193.85 = 105.28 : x
  2. Step 2: Convert to fraction form
    129.40/193.85 = 105.28/x
  3. Step 3: Cross multiply
    129.40x = 193.85 × 105.28
  4. Step 4: Simplify right side
    129.40x = 20,408.53
  5. Step 5: Solve for x
    x = 20,408.53/129.40
  6. Step 6: Final answer
    x = 157.72

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.