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Finding the Fourth Proportional to 80.86, 111.66 and 61.42

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Solution

The fourth proportional to 80.86, 111.66 and 61.42 is: 84.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.86 : 111.66 = 61.42 : x
  2. Step 2: Convert to fraction form
    80.86/111.66 = 61.42/x
  3. Step 3: Cross multiply
    80.86x = 111.66 × 61.42
  4. Step 4: Simplify right side
    80.86x = 6,858.16
  5. Step 5: Solve for x
    x = 6,858.16/80.86
  6. Step 6: Final answer
    x = 84.82

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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.