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Finding the Fourth Proportional to 28.20, 38.91 and 15.92

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Solution

The fourth proportional to 28.20, 38.91 and 15.92 is: 21.97

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.20 : 38.91 = 15.92 : x
  2. Step 2: Convert to fraction form
    28.20/38.91 = 15.92/x
  3. Step 3: Cross multiply
    28.20x = 38.91 × 15.92
  4. Step 4: Simplify right side
    28.20x = 619.49
  5. Step 5: Solve for x
    x = 619.49/28.20
  6. Step 6: Final answer
    x = 21.97

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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.