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Finding the Fourth Proportional to 86.62, 129.92 and 77.07

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Solution

The fourth proportional to 86.62, 129.92 and 77.07 is: 115.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.62 : 129.92 = 77.07 : x
  2. Step 2: Convert to fraction form
    86.62/129.92 = 77.07/x
  3. Step 3: Cross multiply
    86.62x = 129.92 × 77.07
  4. Step 4: Simplify right side
    86.62x = 10,013.26
  5. Step 5: Solve for x
    x = 10,013.26/86.62
  6. Step 6: Final answer
    x = 115.61

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.