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Finding the Fourth Proportional to 86.15, 129.23 and 28.36

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Solution

The fourth proportional to 86.15, 129.23 and 28.36 is: 42.54

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.15 : 129.23 = 28.36 : x
  2. Step 2: Convert to fraction form
    86.15/129.23 = 28.36/x
  3. Step 3: Cross multiply
    86.15x = 129.23 × 28.36
  4. Step 4: Simplify right side
    86.15x = 3,664.96
  5. Step 5: Solve for x
    x = 3,664.96/86.15
  6. Step 6: Final answer
    x = 42.54

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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.