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Finding the Fourth Proportional to 129.09, 192.39 and 128.28

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Solution

The fourth proportional to 129.09, 192.39 and 128.28 is: 191.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    129.09 : 192.39 = 128.28 : x
  2. Step 2: Convert to fraction form
    129.09/192.39 = 128.28/x
  3. Step 3: Cross multiply
    129.09x = 192.39 × 128.28
  4. Step 4: Simplify right side
    129.09x = 24,679.79
  5. Step 5: Solve for x
    x = 24,679.79/129.09
  6. Step 6: Final answer
    x = 191.18

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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.