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Finding the Fourth Proportional to 28.25, 42.39 and 12.21

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Solution

The fourth proportional to 28.25, 42.39 and 12.21 is: 18.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.25 : 42.39 = 12.21 : x
  2. Step 2: Convert to fraction form
    28.25/42.39 = 12.21/x
  3. Step 3: Cross multiply
    28.25x = 42.39 × 12.21
  4. Step 4: Simplify right side
    28.25x = 517.58
  5. Step 5: Solve for x
    x = 517.58/28.25
  6. Step 6: Final answer
    x = 18.32

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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.