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Finding the Fourth Proportional to 28.77, 39.71 and 21.88

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Solution

The fourth proportional to 28.77, 39.71 and 21.88 is: 30.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.77 : 39.71 = 21.88 : x
  2. Step 2: Convert to fraction form
    28.77/39.71 = 21.88/x
  3. Step 3: Cross multiply
    28.77x = 39.71 × 21.88
  4. Step 4: Simplify right side
    28.77x = 868.96
  5. Step 5: Solve for x
    x = 868.96/28.77
  6. Step 6: Final answer
    x = 30.21

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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.