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Finding the Fourth Proportional to 129.70, 194.34 and 81.50

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Solution

The fourth proportional to 129.70, 194.34 and 81.50 is: 122.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.70 : 194.34 = 81.50 : x
  2. Step 2: Convert to fraction form
    129.70/194.34 = 81.50/x
  3. Step 3: Cross multiply
    129.70x = 194.34 × 81.50
  4. Step 4: Simplify right side
    129.70x = 15,838.71
  5. Step 5: Solve for x
    x = 15,838.71/129.70
  6. Step 6: Final answer
    x = 122.12

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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.