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Finding the Fourth Proportional to 138, 206.82 and 68.63

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Solution

The fourth proportional to 138, 206.82 and 68.63 is: 102.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    138 : 206.82 = 68.63 : x
  2. Step 2: Convert to fraction form
    138/206.82 = 68.63/x
  3. Step 3: Cross multiply
    138x = 206.82 × 68.63
  4. Step 4: Simplify right side
    138x = 14,193.02
  5. Step 5: Solve for x
    x = 14,193.02/138
  6. Step 6: Final answer
    x = 102.85

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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.