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Finding the Fourth Proportional to 68.20, 102.31 and 61.81

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Solution

The fourth proportional to 68.20, 102.31 and 61.81 is: 92.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    68.20 : 102.31 = 61.81 : x
  2. Step 2: Convert to fraction form
    68.20/102.31 = 61.81/x
  3. Step 3: Cross multiply
    68.20x = 102.31 × 61.81
  4. Step 4: Simplify right side
    68.20x = 6,323.37
  5. Step 5: Solve for x
    x = 6,323.37/68.20
  6. Step 6: Final answer
    x = 92.72

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.