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Finding the Fourth Proportional to 77.86, 107.40 and 61.46

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Solution

The fourth proportional to 77.86, 107.40 and 61.46 is: 84.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.86 : 107.40 = 61.46 : x
  2. Step 2: Convert to fraction form
    77.86/107.40 = 61.46/x
  3. Step 3: Cross multiply
    77.86x = 107.40 × 61.46
  4. Step 4: Simplify right side
    77.86x = 6,600.80
  5. Step 5: Solve for x
    x = 6,600.80/77.86
  6. Step 6: Final answer
    x = 84.78

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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.