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Finding the Fourth Proportional to 28.89, 39.81 and 21.60

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Solution

The fourth proportional to 28.89, 39.81 and 21.60 is: 29.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.89 : 39.81 = 21.60 : x
  2. Step 2: Convert to fraction form
    28.89/39.81 = 21.60/x
  3. Step 3: Cross multiply
    28.89x = 39.81 × 21.60
  4. Step 4: Simplify right side
    28.89x = 859.90
  5. Step 5: Solve for x
    x = 859.90/28.89
  6. Step 6: Final answer
    x = 29.76

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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.