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Finding the Fourth Proportional to 6.61, 9.90 and 5.56

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Solution

The fourth proportional to 6.61, 9.90 and 5.56 is: 8.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    6.61 : 9.90 = 5.56 : x
  2. Step 2: Convert to fraction form
    6.61/9.90 = 5.56/x
  3. Step 3: Cross multiply
    6.61x = 9.90 × 5.56
  4. Step 4: Simplify right side
    6.61x = 54.97
  5. Step 5: Solve for x
    x = 54.97/6.61
  6. Step 6: Final answer
    x = 8.32

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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.