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Finding the Fourth Proportional to 7.90, 10.91 and 6.89

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Solution

The fourth proportional to 7.90, 10.91 and 6.89 is: 9.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    7.90 : 10.91 = 6.89 : x
  2. Step 2: Convert to fraction form
    7.90/10.91 = 6.89/x
  3. Step 3: Cross multiply
    7.90x = 10.91 × 6.89
  4. Step 4: Simplify right side
    7.90x = 75.14
  5. Step 5: Solve for x
    x = 75.14/7.90
  6. Step 6: Final answer
    x = 9.52

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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.