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Finding the Fourth Proportional to 3.86, 5.78 and 1.85

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Solution

The fourth proportional to 3.86, 5.78 and 1.85 is: 2.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    3.86 : 5.78 = 1.85 : x
  2. Step 2: Convert to fraction form
    3.86/5.78 = 1.85/x
  3. Step 3: Cross multiply
    3.86x = 5.78 × 1.85
  4. Step 4: Simplify right side
    3.86x = 10.71
  5. Step 5: Solve for x
    x = 10.71/3.86
  6. Step 6: Final answer
    x = 2.78

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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.