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Finding the Fourth Proportional to 89.85, 133.89 and 86.58

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Solution

The fourth proportional to 89.85, 133.89 and 86.58 is: 129.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.85 : 133.89 = 86.58 : x
  2. Step 2: Convert to fraction form
    89.85/133.89 = 86.58/x
  3. Step 3: Cross multiply
    89.85x = 133.89 × 86.58
  4. Step 4: Simplify right side
    89.85x = 11,592.20
  5. Step 5: Solve for x
    x = 11,592.20/89.85
  6. Step 6: Final answer
    x = 129.02

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.