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Finding the Fourth Proportional to 12.88, 19.36 and 8.40

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Solution

The fourth proportional to 12.88, 19.36 and 8.40 is: 12.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    12.88 : 19.36 = 8.40 : x
  2. Step 2: Convert to fraction form
    12.88/19.36 = 8.40/x
  3. Step 3: Cross multiply
    12.88x = 19.36 × 8.40
  4. Step 4: Simplify right side
    12.88x = 162.73
  5. Step 5: Solve for x
    x = 162.73/12.88
  6. Step 6: Final answer
    x = 12.63

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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.