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Finding the Fourth Proportional to 66.87, 100.17 and 55.31

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Solution

The fourth proportional to 66.87, 100.17 and 55.31 is: 82.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    66.87 : 100.17 = 55.31 : x
  2. Step 2: Convert to fraction form
    66.87/100.17 = 55.31/x
  3. Step 3: Cross multiply
    66.87x = 100.17 × 55.31
  4. Step 4: Simplify right side
    66.87x = 5,539.90
  5. Step 5: Solve for x
    x = 5,539.90/66.87
  6. Step 6: Final answer
    x = 82.85

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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.