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Finding the Fourth Proportional to 81.75, 113.30 and 79.42

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Solution

The fourth proportional to 81.75, 113.30 and 79.42 is: 110.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.75 : 113.30 = 79.42 : x
  2. Step 2: Convert to fraction form
    81.75/113.30 = 79.42/x
  3. Step 3: Cross multiply
    81.75x = 113.30 × 79.42
  4. Step 4: Simplify right side
    81.75x = 8,997.89
  5. Step 5: Solve for x
    x = 8,997.89/81.75
  6. Step 6: Final answer
    x = 110.07

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Why These Related Problems?

These problems maintain the same ratio (1.39) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.