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Finding the Fourth Proportional to 68.60, 102.31 and 61.40

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Solution

The fourth proportional to 68.60, 102.31 and 61.40 is: 91.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    68.60 : 102.31 = 61.40 : x
  2. Step 2: Convert to fraction form
    68.60/102.31 = 61.40/x
  3. Step 3: Cross multiply
    68.60x = 102.31 × 61.40
  4. Step 4: Simplify right side
    68.60x = 6,281.83
  5. Step 5: Solve for x
    x = 6,281.83/68.60
  6. Step 6: Final answer
    x = 91.57

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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.