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Finding the Fourth Proportional to 81, 112.39 and 80.37

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Solution

The fourth proportional to 81, 112.39 and 80.37 is: 111.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    81 : 112.39 = 80.37 : x
  2. Step 2: Convert to fraction form
    81/112.39 = 80.37/x
  3. Step 3: Cross multiply
    81x = 112.39 × 80.37
  4. Step 4: Simplify right side
    81x = 9,032.58
  5. Step 5: Solve for x
    x = 9,032.58/81
  6. Step 6: Final answer
    x = 111.51

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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.