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Finding the Fourth Proportional to 85.87, 118.38 and 72.82

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Solution

The fourth proportional to 85.87, 118.38 and 72.82 is: 100.39

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.87 : 118.38 = 72.82 : x
  2. Step 2: Convert to fraction form
    85.87/118.38 = 72.82/x
  3. Step 3: Cross multiply
    85.87x = 118.38 × 72.82
  4. Step 4: Simplify right side
    85.87x = 8,620.43
  5. Step 5: Solve for x
    x = 8,620.43/85.87
  6. Step 6: Final answer
    x = 100.39

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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.