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Finding the Fourth Proportional to 85.96, 118.74 and 81.91

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Solution

The fourth proportional to 85.96, 118.74 and 81.91 is: 113.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    85.96 : 118.74 = 81.91 : x
  2. Step 2: Convert to fraction form
    85.96/118.74 = 81.91/x
  3. Step 3: Cross multiply
    85.96x = 118.74 × 81.91
  4. Step 4: Simplify right side
    85.96x = 9,725.99
  5. Step 5: Solve for x
    x = 9,725.99/85.96
  6. Step 6: Final answer
    x = 113.15

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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.