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Finding the Fourth Proportional to 28.62, 39.42 and 21.33

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Solution

The fourth proportional to 28.62, 39.42 and 21.33 is: 29.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.62 : 39.42 = 21.33 : x
  2. Step 2: Convert to fraction form
    28.62/39.42 = 21.33/x
  3. Step 3: Cross multiply
    28.62x = 39.42 × 21.33
  4. Step 4: Simplify right side
    28.62x = 840.83
  5. Step 5: Solve for x
    x = 840.83/28.62
  6. Step 6: Final answer
    x = 29.38

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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.