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Finding the Fourth Proportional to 81.55, 122.42 and 61.10

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Solution

The fourth proportional to 81.55, 122.42 and 61.10 is: 91.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.55 : 122.42 = 61.10 : x
  2. Step 2: Convert to fraction form
    81.55/122.42 = 61.10/x
  3. Step 3: Cross multiply
    81.55x = 122.42 × 61.10
  4. Step 4: Simplify right side
    81.55x = 7,479.40
  5. Step 5: Solve for x
    x = 7,479.40/81.55
  6. Step 6: Final answer
    x = 91.72

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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.