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Finding the Fourth Proportional to 90.83, 136.91 and 85.88

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Solution

The fourth proportional to 90.83, 136.91 and 85.88 is: 129.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    90.83 : 136.91 = 85.88 : x
  2. Step 2: Convert to fraction form
    90.83/136.91 = 85.88/x
  3. Step 3: Cross multiply
    90.83x = 136.91 × 85.88
  4. Step 4: Simplify right side
    90.83x = 11,757.74
  5. Step 5: Solve for x
    x = 11,757.74/90.83
  6. Step 6: Final answer
    x = 129.44

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.