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Finding the Fourth Proportional to 12.90, 17.80 and 11.79

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Solution

The fourth proportional to 12.90, 17.80 and 11.79 is: 16.27

Step by Step Solution

  1. Step 1: Write the proportion equation
    12.90 : 17.80 = 11.79 : x
  2. Step 2: Convert to fraction form
    12.90/17.80 = 11.79/x
  3. Step 3: Cross multiply
    12.90x = 17.80 × 11.79
  4. Step 4: Simplify right side
    12.90x = 209.80
  5. Step 5: Solve for x
    x = 209.80/12.90
  6. Step 6: Final answer
    x = 16.27

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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.