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Finding the Fourth Proportional to 128.54, 192.54 and 121.70

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Solution

The fourth proportional to 128.54, 192.54 and 121.70 is: 182.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.54 : 192.54 = 121.70 : x
  2. Step 2: Convert to fraction form
    128.54/192.54 = 121.70/x
  3. Step 3: Cross multiply
    128.54x = 192.54 × 121.70
  4. Step 4: Simplify right side
    128.54x = 23,432.12
  5. Step 5: Solve for x
    x = 23,432.12/128.54
  6. Step 6: Final answer
    x = 182.29

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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.