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Finding the Fourth Proportional to 86.66, 129.97 and 25.78

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Solution

The fourth proportional to 86.66, 129.97 and 25.78 is: 38.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.66 : 129.97 = 25.78 : x
  2. Step 2: Convert to fraction form
    86.66/129.97 = 25.78/x
  3. Step 3: Cross multiply
    86.66x = 129.97 × 25.78
  4. Step 4: Simplify right side
    86.66x = 3,350.24
  5. Step 5: Solve for x
    x = 3,350.24/86.66
  6. Step 6: Final answer
    x = 38.66

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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.