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Finding the Fourth Proportional to 10.87, 16.28 and 8.61

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Solution

The fourth proportional to 10.87, 16.28 and 8.61 is: 12.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    10.87 : 16.28 = 8.61 : x
  2. Step 2: Convert to fraction form
    10.87/16.28 = 8.61/x
  3. Step 3: Cross multiply
    10.87x = 16.28 × 8.61
  4. Step 4: Simplify right side
    10.87x = 140.17
  5. Step 5: Solve for x
    x = 140.17/10.87
  6. Step 6: Final answer
    x = 12.90

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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.