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Finding the Fourth Proportional to 81.32, 112.06 and 78.36

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Solution

The fourth proportional to 81.32, 112.06 and 78.36 is: 107.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.32 : 112.06 = 78.36 : x
  2. Step 2: Convert to fraction form
    81.32/112.06 = 78.36/x
  3. Step 3: Cross multiply
    81.32x = 112.06 × 78.36
  4. Step 4: Simplify right side
    81.32x = 8,781.02
  5. Step 5: Solve for x
    x = 8,781.02/81.32
  6. Step 6: Final answer
    x = 107.98

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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.