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Finding the Fourth Proportional to 86.09, 129.15 and 54

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Solution

The fourth proportional to 86.09, 129.15 and 54 is: 81.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.09 : 129.15 = 54 : x
  2. Step 2: Convert to fraction form
    86.09/129.15 = 54/x
  3. Step 3: Cross multiply
    86.09x = 129.15 × 54
  4. Step 4: Simplify right side
    86.09x = 6,974.10
  5. Step 5: Solve for x
    x = 6,974.10/86.09
  6. Step 6: Final answer
    x = 81.01

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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.