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Finding the Fourth Proportional to 28.97, 39.98 and 20.81

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Solution

The fourth proportional to 28.97, 39.98 and 20.81 is: 28.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.97 : 39.98 = 20.81 : x
  2. Step 2: Convert to fraction form
    28.97/39.98 = 20.81/x
  3. Step 3: Cross multiply
    28.97x = 39.98 × 20.81
  4. Step 4: Simplify right side
    28.97x = 831.88
  5. Step 5: Solve for x
    x = 831.88/28.97
  6. Step 6: Final answer
    x = 28.72

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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.