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Finding the Fourth Proportional to 28.12, 42.20 and 25.76

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Solution

The fourth proportional to 28.12, 42.20 and 25.76 is: 38.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.12 : 42.20 = 25.76 : x
  2. Step 2: Convert to fraction form
    28.12/42.20 = 25.76/x
  3. Step 3: Cross multiply
    28.12x = 42.20 × 25.76
  4. Step 4: Simplify right side
    28.12x = 1,087.07
  5. Step 5: Solve for x
    x = 1,087.07/28.12
  6. Step 6: Final answer
    x = 38.66

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.