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Finding the Fourth Proportional to 28.38, 42.54 and 20.40

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Solution

The fourth proportional to 28.38, 42.54 and 20.40 is: 30.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    28.38 : 42.54 = 20.40 : x
  2. Step 2: Convert to fraction form
    28.38/42.54 = 20.40/x
  3. Step 3: Cross multiply
    28.38x = 42.54 × 20.40
  4. Step 4: Simplify right side
    28.38x = 867.82
  5. Step 5: Solve for x
    x = 867.82/28.38
  6. Step 6: Final answer
    x = 30.58

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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.