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Finding the Fourth Proportional to 85.06, 117.21 and 81.87

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Solution

The fourth proportional to 85.06, 117.21 and 81.87 is: 112.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.06 : 117.21 = 81.87 : x
  2. Step 2: Convert to fraction form
    85.06/117.21 = 81.87/x
  3. Step 3: Cross multiply
    85.06x = 117.21 × 81.87
  4. Step 4: Simplify right side
    85.06x = 9,595.98
  5. Step 5: Solve for x
    x = 9,595.98/85.06
  6. Step 6: Final answer
    x = 112.81

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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.