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Finding the Fourth Proportional to 12.78, 19.02 and 12.71

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Solution

The fourth proportional to 12.78, 19.02 and 12.71 is: 18.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    12.78 : 19.02 = 12.71 : x
  2. Step 2: Convert to fraction form
    12.78/19.02 = 12.71/x
  3. Step 3: Cross multiply
    12.78x = 19.02 × 12.71
  4. Step 4: Simplify right side
    12.78x = 241.65
  5. Step 5: Solve for x
    x = 241.65/12.78
  6. Step 6: Final answer
    x = 18.91

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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.