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Finding the Fourth Proportional to 81.25, 111.39 and 79.79

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Solution

The fourth proportional to 81.25, 111.39 and 79.79 is: 109.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.25 : 111.39 = 79.79 : x
  2. Step 2: Convert to fraction form
    81.25/111.39 = 79.79/x
  3. Step 3: Cross multiply
    81.25x = 111.39 × 79.79
  4. Step 4: Simplify right side
    81.25x = 8,887.53
  5. Step 5: Solve for x
    x = 8,887.53/81.25
  6. Step 6: Final answer
    x = 109.39

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.