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Finding the Fourth Proportional to 86.60, 119.31 and 81.38

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Solution

The fourth proportional to 86.60, 119.31 and 81.38 is: 112.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.60 : 119.31 = 81.38 : x
  2. Step 2: Convert to fraction form
    86.60/119.31 = 81.38/x
  3. Step 3: Cross multiply
    86.60x = 119.31 × 81.38
  4. Step 4: Simplify right side
    86.60x = 9,709.45
  5. Step 5: Solve for x
    x = 9,709.45/86.60
  6. Step 6: Final answer
    x = 112.12

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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.