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Finding the Fourth Proportional to 6.61, 9.90 and 3.93

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Solution

The fourth proportional to 6.61, 9.90 and 3.93 is: 5.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    6.61 : 9.90 = 3.93 : x
  2. Step 2: Convert to fraction form
    6.61/9.90 = 3.93/x
  3. Step 3: Cross multiply
    6.61x = 9.90 × 3.93
  4. Step 4: Simplify right side
    6.61x = 38.91
  5. Step 5: Solve for x
    x = 38.91/6.61
  6. Step 6: Final answer
    x = 5.89

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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.