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Finding the Fourth Proportional to 11.85, 17.78 and 7.85

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Solution

The fourth proportional to 11.85, 17.78 and 7.85 is: 11.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    11.85 : 17.78 = 7.85 : x
  2. Step 2: Convert to fraction form
    11.85/17.78 = 7.85/x
  3. Step 3: Cross multiply
    11.85x = 17.78 × 7.85
  4. Step 4: Simplify right side
    11.85x = 139.44
  5. Step 5: Solve for x
    x = 139.44/11.85
  6. Step 6: Final answer
    x = 11.77

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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.