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Finding the Fourth Proportional to 7.15, 9.80 and 6.85

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Solution

The fourth proportional to 7.15, 9.80 and 6.85 is: 9.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    7.15 : 9.80 = 6.85 : x
  2. Step 2: Convert to fraction form
    7.15/9.80 = 6.85/x
  3. Step 3: Cross multiply
    7.15x = 9.80 × 6.85
  4. Step 4: Simplify right side
    7.15x = 67.13
  5. Step 5: Solve for x
    x = 67.13/7.15
  6. Step 6: Final answer
    x = 9.39

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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.