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Finding the Fourth Proportional to 19.81, 29.72 and 18.85

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Solution

The fourth proportional to 19.81, 29.72 and 18.85 is: 28.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    19.81 : 29.72 = 18.85 : x
  2. Step 2: Convert to fraction form
    19.81/29.72 = 18.85/x
  3. Step 3: Cross multiply
    19.81x = 29.72 × 18.85
  4. Step 4: Simplify right side
    19.81x = 560.22
  5. Step 5: Solve for x
    x = 560.22/19.81
  6. Step 6: Final answer
    x = 28.28

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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.