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Finding the Fourth Proportional to 28.09, 38.71 and 21.61

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Solution

The fourth proportional to 28.09, 38.71 and 21.61 is: 29.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.09 : 38.71 = 21.61 : x
  2. Step 2: Convert to fraction form
    28.09/38.71 = 21.61/x
  3. Step 3: Cross multiply
    28.09x = 38.71 × 21.61
  4. Step 4: Simplify right side
    28.09x = 836.52
  5. Step 5: Solve for x
    x = 836.52/28.09
  6. Step 6: Final answer
    x = 29.78

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.