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Finding the Fourth Proportional to 81.25, 112.70 and 78.41

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Solution

The fourth proportional to 81.25, 112.70 and 78.41 is: 108.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.25 : 112.70 = 78.41 : x
  2. Step 2: Convert to fraction form
    81.25/112.70 = 78.41/x
  3. Step 3: Cross multiply
    81.25x = 112.70 × 78.41
  4. Step 4: Simplify right side
    81.25x = 8,837.28
  5. Step 5: Solve for x
    x = 8,837.28/81.25
  6. Step 6: Final answer
    x = 108.77

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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.