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Finding the Fourth Proportional to 81.90, 113.13 and 79.92

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Solution

The fourth proportional to 81.90, 113.13 and 79.92 is: 110.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.90 : 113.13 = 79.92 : x
  2. Step 2: Convert to fraction form
    81.90/113.13 = 79.92/x
  3. Step 3: Cross multiply
    81.90x = 113.13 × 79.92
  4. Step 4: Simplify right side
    81.90x = 9,041.35
  5. Step 5: Solve for x
    x = 9,041.35/81.90
  6. Step 6: Final answer
    x = 110.39

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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.