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Finding the Fourth Proportional to 19.87, 29.81 and 18.72

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Solution

The fourth proportional to 19.87, 29.81 and 18.72 is: 28.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    19.87 : 29.81 = 18.72 : x
  2. Step 2: Convert to fraction form
    19.87/29.81 = 18.72/x
  3. Step 3: Cross multiply
    19.87x = 29.81 × 18.72
  4. Step 4: Simplify right side
    19.87x = 558.09
  5. Step 5: Solve for x
    x = 558.09/19.87
  6. Step 6: Final answer
    x = 28.09

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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.