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Finding the Fourth Proportional to 7.20, 9.90 and 6.66

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Solution

The fourth proportional to 7.20, 9.90 and 6.66 is: 9.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    7.20 : 9.90 = 6.66 : x
  2. Step 2: Convert to fraction form
    7.20/9.90 = 6.66/x
  3. Step 3: Cross multiply
    7.20x = 9.90 × 6.66
  4. Step 4: Simplify right side
    7.20x = 65.93
  5. Step 5: Solve for x
    x = 65.93/7.20
  6. Step 6: Final answer
    x = 9.16

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.