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Finding the Fourth Proportional to 28.78, 43.09 and 18.61

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Solution

The fourth proportional to 28.78, 43.09 and 18.61 is: 27.86

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.78 : 43.09 = 18.61 : x
  2. Step 2: Convert to fraction form
    28.78/43.09 = 18.61/x
  3. Step 3: Cross multiply
    28.78x = 43.09 × 18.61
  4. Step 4: Simplify right side
    28.78x = 801.90
  5. Step 5: Solve for x
    x = 801.90/28.78
  6. Step 6: Final answer
    x = 27.86

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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.