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Finding the Fourth Proportional to 81.36, 112.32 and 80.16

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Solution

The fourth proportional to 81.36, 112.32 and 80.16 is: 110.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    81.36 : 112.32 = 80.16 : x
  2. Step 2: Convert to fraction form
    81.36/112.32 = 80.16/x
  3. Step 3: Cross multiply
    81.36x = 112.32 × 80.16
  4. Step 4: Simplify right side
    81.36x = 9,003.57
  5. Step 5: Solve for x
    x = 9,003.57/81.36
  6. Step 6: Final answer
    x = 110.66

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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.