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Finding the Fourth Proportional to 86.86, 129.65 and 85.06

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Solution

The fourth proportional to 86.86, 129.65 and 85.06 is: 126.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.86 : 129.65 = 85.06 : x
  2. Step 2: Convert to fraction form
    86.86/129.65 = 85.06/x
  3. Step 3: Cross multiply
    86.86x = 129.65 × 85.06
  4. Step 4: Simplify right side
    86.86x = 11,028.03
  5. Step 5: Solve for x
    x = 11,028.03/86.86
  6. Step 6: Final answer
    x = 126.96

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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.