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Finding the Fourth Proportional to 83.60, 124.78 and 78.92

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Solution

The fourth proportional to 83.60, 124.78 and 78.92 is: 117.79

Step by Step Solution

  1. Step 1: Write the proportion equation
    83.60 : 124.78 = 78.92 : x
  2. Step 2: Convert to fraction form
    83.60/124.78 = 78.92/x
  3. Step 3: Cross multiply
    83.60x = 124.78 × 78.92
  4. Step 4: Simplify right side
    83.60x = 9,847.64
  5. Step 5: Solve for x
    x = 9,847.64/83.60
  6. Step 6: Final answer
    x = 117.79

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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.