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Finding the Fourth Proportional to 107.70, 148.62 and 81.78

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Solution

The fourth proportional to 107.70, 148.62 and 81.78 is: 112.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    107.70 : 148.62 = 81.78 : x
  2. Step 2: Convert to fraction form
    107.70/148.62 = 81.78/x
  3. Step 3: Cross multiply
    107.70x = 148.62 × 81.78
  4. Step 4: Simplify right side
    107.70x = 12,154.14
  5. Step 5: Solve for x
    x = 12,154.14/107.70
  6. Step 6: Final answer
    x = 112.85

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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.