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Finding the Fourth Proportional to 8.12, 11.15 and 6.90

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Solution

The fourth proportional to 8.12, 11.15 and 6.90 is: 9.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    8.12 : 11.15 = 6.90 : x
  2. Step 2: Convert to fraction form
    8.12/11.15 = 6.90/x
  3. Step 3: Cross multiply
    8.12x = 11.15 × 6.90
  4. Step 4: Simplify right side
    8.12x = 76.94
  5. Step 5: Solve for x
    x = 76.94/8.12
  6. Step 6: Final answer
    x = 9.47

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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.