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Finding the Fourth Proportional to 12.91, 19.38 and 10.90

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Solution

The fourth proportional to 12.91, 19.38 and 10.90 is: 16.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    12.91 : 19.38 = 10.90 : x
  2. Step 2: Convert to fraction form
    12.91/19.38 = 10.90/x
  3. Step 3: Cross multiply
    12.91x = 19.38 × 10.90
  4. Step 4: Simplify right side
    12.91x = 211.24
  5. Step 5: Solve for x
    x = 211.24/12.91
  6. Step 6: Final answer
    x = 16.36

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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.