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Finding the Fourth Proportional to 86.38, 129.44 and 77.22

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Solution

The fourth proportional to 86.38, 129.44 and 77.22 is: 115.71

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.38 : 129.44 = 77.22 : x
  2. Step 2: Convert to fraction form
    86.38/129.44 = 77.22/x
  3. Step 3: Cross multiply
    86.38x = 129.44 × 77.22
  4. Step 4: Simplify right side
    86.38x = 9,994.32
  5. Step 5: Solve for x
    x = 9,994.32/86.38
  6. Step 6: Final answer
    x = 115.71

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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.