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Finding the Fourth Proportional to 11.90, 15.78 and 11.90

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Solution

The fourth proportional to 11.90, 15.78 and 11.90 is: 15.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    11.90 : 15.78 = 11.90 : x
  2. Step 2: Convert to fraction form
    11.90/15.78 = 11.90/x
  3. Step 3: Cross multiply
    11.90x = 15.78 × 11.90
  4. Step 4: Simplify right side
    11.90x = 187.78
  5. Step 5: Solve for x
    x = 187.78/11.90
  6. Step 6: Final answer
    x = 15.78

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Why These Related Problems?

These problems maintain the same ratio (1.33) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.