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Finding the Fourth Proportional to 86.44, 129.10 and 81.79

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Solution

The fourth proportional to 86.44, 129.10 and 81.79 is: 122.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.44 : 129.10 = 81.79 : x
  2. Step 2: Convert to fraction form
    86.44/129.10 = 81.79/x
  3. Step 3: Cross multiply
    86.44x = 129.10 × 81.79
  4. Step 4: Simplify right side
    86.44x = 10,558.03
  5. Step 5: Solve for x
    x = 10,558.03/86.44
  6. Step 6: Final answer
    x = 122.14

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.