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Finding the Fourth Proportional to 7.11, 9.72 and 6.90

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Solution

The fourth proportional to 7.11, 9.72 and 6.90 is: 9.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    7.11 : 9.72 = 6.90 : x
  2. Step 2: Convert to fraction form
    7.11/9.72 = 6.90/x
  3. Step 3: Cross multiply
    7.11x = 9.72 × 6.90
  4. Step 4: Simplify right side
    7.11x = 67.07
  5. Step 5: Solve for x
    x = 67.07/7.11
  6. Step 6: Final answer
    x = 9.43

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.