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Finding the Fourth Proportional to 14.78, 20.40 and 8.31

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Solution

The fourth proportional to 14.78, 20.40 and 8.31 is: 11.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    14.78 : 20.40 = 8.31 : x
  2. Step 2: Convert to fraction form
    14.78/20.40 = 8.31/x
  3. Step 3: Cross multiply
    14.78x = 20.40 × 8.31
  4. Step 4: Simplify right side
    14.78x = 169.55
  5. Step 5: Solve for x
    x = 169.55/14.78
  6. Step 6: Final answer
    x = 11.47

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.