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Finding the Fourth Proportional to 8.58, 12.90 and 6.78

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Solution

The fourth proportional to 8.58, 12.90 and 6.78 is: 10.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    8.58 : 12.90 = 6.78 : x
  2. Step 2: Convert to fraction form
    8.58/12.90 = 6.78/x
  3. Step 3: Cross multiply
    8.58x = 12.90 × 6.78
  4. Step 4: Simplify right side
    8.58x = 87.46
  5. Step 5: Solve for x
    x = 87.46/8.58
  6. Step 6: Final answer
    x = 10.19

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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.