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Finding the Fourth Proportional to 7.86, 10.81 and 6.78

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Solution

The fourth proportional to 7.86, 10.81 and 6.78 is: 9.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    7.86 : 10.81 = 6.78 : x
  2. Step 2: Convert to fraction form
    7.86/10.81 = 6.78/x
  3. Step 3: Cross multiply
    7.86x = 10.81 × 6.78
  4. Step 4: Simplify right side
    7.86x = 73.29
  5. Step 5: Solve for x
    x = 73.29/7.86
  6. Step 6: Final answer
    x = 9.32

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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.