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Finding the Fourth Proportional to 86.67, 129.78 and 68.58

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Solution

The fourth proportional to 86.67, 129.78 and 68.58 is: 102.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.67 : 129.78 = 68.58 : x
  2. Step 2: Convert to fraction form
    86.67/129.78 = 68.58/x
  3. Step 3: Cross multiply
    86.67x = 129.78 × 68.58
  4. Step 4: Simplify right side
    86.67x = 8,900.31
  5. Step 5: Solve for x
    x = 8,900.31/86.67
  6. Step 6: Final answer
    x = 102.69

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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.