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Finding the Fourth Proportional to 42.54, 63.84 and 20.91

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Solution

The fourth proportional to 42.54, 63.84 and 20.91 is: 31.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    42.54 : 63.84 = 20.91 : x
  2. Step 2: Convert to fraction form
    42.54/63.84 = 20.91/x
  3. Step 3: Cross multiply
    42.54x = 63.84 × 20.91
  4. Step 4: Simplify right side
    42.54x = 1,334.89
  5. Step 5: Solve for x
    x = 1,334.89/42.54
  6. Step 6: Final answer
    x = 31.38

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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.