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Finding the Fourth Proportional to 28.47, 39.27 and 21.09

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Solution

The fourth proportional to 28.47, 39.27 and 21.09 is: 29.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.47 : 39.27 = 21.09 : x
  2. Step 2: Convert to fraction form
    28.47/39.27 = 21.09/x
  3. Step 3: Cross multiply
    28.47x = 39.27 × 21.09
  4. Step 4: Simplify right side
    28.47x = 828.20
  5. Step 5: Solve for x
    x = 828.20/28.47
  6. Step 6: Final answer
    x = 29.09

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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.