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Finding the Fourth Proportional to 18.75, 28.17 and 12.78

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Solution

The fourth proportional to 18.75, 28.17 and 12.78 is: 19.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    18.75 : 28.17 = 12.78 : x
  2. Step 2: Convert to fraction form
    18.75/28.17 = 12.78/x
  3. Step 3: Cross multiply
    18.75x = 28.17 × 12.78
  4. Step 4: Simplify right side
    18.75x = 359.87
  5. Step 5: Solve for x
    x = 359.87/18.75
  6. Step 6: Final answer
    x = 19.20

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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.