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Finding the Fourth Proportional to 86.15, 129.26 and 34.78

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Solution

The fourth proportional to 86.15, 129.26 and 34.78 is: 52.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.15 : 129.26 = 34.78 : x
  2. Step 2: Convert to fraction form
    86.15/129.26 = 34.78/x
  3. Step 3: Cross multiply
    86.15x = 129.26 × 34.78
  4. Step 4: Simplify right side
    86.15x = 4,495.66
  5. Step 5: Solve for x
    x = 4,495.66/86.15
  6. Step 6: Final answer
    x = 52.18

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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.