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Finding the Fourth Proportional to 81.75, 113.25 and 78.06

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Solution

The fourth proportional to 81.75, 113.25 and 78.06 is: 108.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.75 : 113.25 = 78.06 : x
  2. Step 2: Convert to fraction form
    81.75/113.25 = 78.06/x
  3. Step 3: Cross multiply
    81.75x = 113.25 × 78.06
  4. Step 4: Simplify right side
    81.75x = 8,840.30
  5. Step 5: Solve for x
    x = 8,840.30/81.75
  6. Step 6: Final answer
    x = 108.14

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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.