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Finding the Fourth Proportional to 28.35, 39.11 and 21.47

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Solution

The fourth proportional to 28.35, 39.11 and 21.47 is: 29.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.35 : 39.11 = 21.47 : x
  2. Step 2: Convert to fraction form
    28.35/39.11 = 21.47/x
  3. Step 3: Cross multiply
    28.35x = 39.11 × 21.47
  4. Step 4: Simplify right side
    28.35x = 839.69
  5. Step 5: Solve for x
    x = 839.69/28.35
  6. Step 6: Final answer
    x = 29.62

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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.