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Finding the Fourth Proportional to 129.71, 194.42 and 71.90

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Solution

The fourth proportional to 129.71, 194.42 and 71.90 is: 107.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.71 : 194.42 = 71.90 : x
  2. Step 2: Convert to fraction form
    129.71/194.42 = 71.90/x
  3. Step 3: Cross multiply
    129.71x = 194.42 × 71.90
  4. Step 4: Simplify right side
    129.71x = 13,977.47
  5. Step 5: Solve for x
    x = 13,977.47/129.71
  6. Step 6: Final answer
    x = 107.76

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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.