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Finding the Fourth Proportional to 86.87, 130.14 and 81.88

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Solution

The fourth proportional to 86.87, 130.14 and 81.88 is: 122.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    86.87 : 130.14 = 81.88 : x
  2. Step 2: Convert to fraction form
    86.87/130.14 = 81.88/x
  3. Step 3: Cross multiply
    86.87x = 130.14 × 81.88
  4. Step 4: Simplify right side
    86.87x = 10,655.54
  5. Step 5: Solve for x
    x = 10,655.54/86.87
  6. Step 6: Final answer
    x = 122.66

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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.