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Finding the Fourth Proportional to 77.85, 107.31 and 61.14

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Solution

The fourth proportional to 77.85, 107.31 and 61.14 is: 84.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    77.85 : 107.31 = 61.14 : x
  2. Step 2: Convert to fraction form
    77.85/107.31 = 61.14/x
  3. Step 3: Cross multiply
    77.85x = 107.31 × 61.14
  4. Step 4: Simplify right side
    77.85x = 6,560.93
  5. Step 5: Solve for x
    x = 6,560.93/77.85
  6. Step 6: Final answer
    x = 84.28

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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.