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Finding the Fourth Proportional to 128.29, 192.15 and 80.11

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Solution

The fourth proportional to 128.29, 192.15 and 80.11 is: 119.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.29 : 192.15 = 80.11 : x
  2. Step 2: Convert to fraction form
    128.29/192.15 = 80.11/x
  3. Step 3: Cross multiply
    128.29x = 192.15 × 80.11
  4. Step 4: Simplify right side
    128.29x = 15,393.14
  5. Step 5: Solve for x
    x = 15,393.14/128.29
  6. Step 6: Final answer
    x = 119.99

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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.