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Finding the Fourth Proportional to 42.08, 63.24 and 20.72

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Solution

The fourth proportional to 42.08, 63.24 and 20.72 is: 31.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    42.08 : 63.24 = 20.72 : x
  2. Step 2: Convert to fraction form
    42.08/63.24 = 20.72/x
  3. Step 3: Cross multiply
    42.08x = 63.24 × 20.72
  4. Step 4: Simplify right side
    42.08x = 1,310.33
  5. Step 5: Solve for x
    x = 1,310.33/42.08
  6. Step 6: Final answer
    x = 31.14

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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.