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Finding the Fourth Proportional to 129.42, 192.86 and 128.36

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Solution

The fourth proportional to 129.42, 192.86 and 128.36 is: 191.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.42 : 192.86 = 128.36 : x
  2. Step 2: Convert to fraction form
    129.42/192.86 = 128.36/x
  3. Step 3: Cross multiply
    129.42x = 192.86 × 128.36
  4. Step 4: Simplify right side
    129.42x = 24,753.90
  5. Step 5: Solve for x
    x = 24,753.90/129.42
  6. Step 6: Final answer
    x = 191.27

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.