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Finding the Fourth Proportional to 103.19, 142.25 and 81.09

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Solution

The fourth proportional to 103.19, 142.25 and 81.09 is: 111.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    103.19 : 142.25 = 81.09 : x
  2. Step 2: Convert to fraction form
    103.19/142.25 = 81.09/x
  3. Step 3: Cross multiply
    103.19x = 142.25 × 81.09
  4. Step 4: Simplify right side
    103.19x = 11,534.65
  5. Step 5: Solve for x
    x = 11,534.65/103.19
  6. Step 6: Final answer
    x = 111.79

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.