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Finding the Fourth Proportional to 128.28, 192.12 and 91.83

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Solution

The fourth proportional to 128.28, 192.12 and 91.83 is: 137.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    128.28 : 192.12 = 91.83 : x
  2. Step 2: Convert to fraction form
    128.28/192.12 = 91.83/x
  3. Step 3: Cross multiply
    128.28x = 192.12 × 91.83
  4. Step 4: Simplify right side
    128.28x = 17,642.38
  5. Step 5: Solve for x
    x = 17,642.38/128.28
  6. Step 6: Final answer
    x = 137.53

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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.