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Finding the Fourth Proportional to 107.72, 161.40 and 69.12

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Solution

The fourth proportional to 107.72, 161.40 and 69.12 is: 103.56

Step by Step Solution

  1. Step 1: Write the proportion equation
    107.72 : 161.40 = 69.12 : x
  2. Step 2: Convert to fraction form
    107.72/161.40 = 69.12/x
  3. Step 3: Cross multiply
    107.72x = 161.40 × 69.12
  4. Step 4: Simplify right side
    107.72x = 11,155.97
  5. Step 5: Solve for x
    x = 11,155.97/107.72
  6. Step 6: Final answer
    x = 103.56

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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.