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Finding the Fourth Proportional to 28.86, 39.87 and 21.98

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Solution

The fourth proportional to 28.86, 39.87 and 21.98 is: 30.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.86 : 39.87 = 21.98 : x
  2. Step 2: Convert to fraction form
    28.86/39.87 = 21.98/x
  3. Step 3: Cross multiply
    28.86x = 39.87 × 21.98
  4. Step 4: Simplify right side
    28.86x = 876.14
  5. Step 5: Solve for x
    x = 876.14/28.86
  6. Step 6: Final answer
    x = 30.36

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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.