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Finding the Fourth Proportional to 20.18, 30.12 and 18.72

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Solution

The fourth proportional to 20.18, 30.12 and 18.72 is: 27.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    20.18 : 30.12 = 18.72 : x
  2. Step 2: Convert to fraction form
    20.18/30.12 = 18.72/x
  3. Step 3: Cross multiply
    20.18x = 30.12 × 18.72
  4. Step 4: Simplify right side
    20.18x = 563.85
  5. Step 5: Solve for x
    x = 563.85/20.18
  6. Step 6: Final answer
    x = 27.94

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.