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Finding the Fourth Proportional to 69.60, 103.92 and 66.88

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Solution

The fourth proportional to 69.60, 103.92 and 66.88 is: 99.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    69.60 : 103.92 = 66.88 : x
  2. Step 2: Convert to fraction form
    69.60/103.92 = 66.88/x
  3. Step 3: Cross multiply
    69.60x = 103.92 × 66.88
  4. Step 4: Simplify right side
    69.60x = 6,950.17
  5. Step 5: Solve for x
    x = 6,950.17/69.60
  6. Step 6: Final answer
    x = 99.86

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.