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Finding the Fourth Proportional to 86.18, 119.43 and 81.05

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Solution

The fourth proportional to 86.18, 119.43 and 81.05 is: 112.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.18 : 119.43 = 81.05 : x
  2. Step 2: Convert to fraction form
    86.18/119.43 = 81.05/x
  3. Step 3: Cross multiply
    86.18x = 119.43 × 81.05
  4. Step 4: Simplify right side
    86.18x = 9,679.80
  5. Step 5: Solve for x
    x = 9,679.80/86.18
  6. Step 6: Final answer
    x = 112.32

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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.