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Finding the Fourth Proportional to 128.67, 192.70 and 82.88

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Solution

The fourth proportional to 128.67, 192.70 and 82.88 is: 124.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.67 : 192.70 = 82.88 : x
  2. Step 2: Convert to fraction form
    128.67/192.70 = 82.88/x
  3. Step 3: Cross multiply
    128.67x = 192.70 × 82.88
  4. Step 4: Simplify right side
    128.67x = 15,970.98
  5. Step 5: Solve for x
    x = 15,970.98/128.67
  6. Step 6: Final answer
    x = 124.12

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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.