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Finding the Fourth Proportional to 8.55, 12.86 and 7.82

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Solution

The fourth proportional to 8.55, 12.86 and 7.82 is: 11.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    8.55 : 12.86 = 7.82 : x
  2. Step 2: Convert to fraction form
    8.55/12.86 = 7.82/x
  3. Step 3: Cross multiply
    8.55x = 12.86 × 7.82
  4. Step 4: Simplify right side
    8.55x = 100.46
  5. Step 5: Solve for x
    x = 100.46/8.55
  6. Step 6: Final answer
    x = 11.75

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.