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Finding the Fourth Proportional to 105.28, 157.92 and 81.38

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Solution

The fourth proportional to 105.28, 157.92 and 81.38 is: 122.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    105.28 : 157.92 = 81.38 : x
  2. Step 2: Convert to fraction form
    105.28/157.92 = 81.38/x
  3. Step 3: Cross multiply
    105.28x = 157.92 × 81.38
  4. Step 4: Simplify right side
    105.28x = 12,851.62
  5. Step 5: Solve for x
    x = 12,851.62/105.28
  6. Step 6: Final answer
    x = 122.07

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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.