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Finding the Fourth Proportional to 81.93, 113.10 and 78.48

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Solution

The fourth proportional to 81.93, 113.10 and 78.48 is: 108.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.93 : 113.10 = 78.48 : x
  2. Step 2: Convert to fraction form
    81.93/113.10 = 78.48/x
  3. Step 3: Cross multiply
    81.93x = 113.10 × 78.48
  4. Step 4: Simplify right side
    81.93x = 8,876.09
  5. Step 5: Solve for x
    x = 8,876.09/81.93
  6. Step 6: Final answer
    x = 108.34

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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.