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Finding the Fourth Proportional to 28.20, 38.93 and 21.76

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Solution

The fourth proportional to 28.20, 38.93 and 21.76 is: 30.04

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.20 : 38.93 = 21.76 : x
  2. Step 2: Convert to fraction form
    28.20/38.93 = 21.76/x
  3. Step 3: Cross multiply
    28.20x = 38.93 × 21.76
  4. Step 4: Simplify right side
    28.20x = 847.12
  5. Step 5: Solve for x
    x = 847.12/28.20
  6. Step 6: Final answer
    x = 30.04

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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.