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Finding the Fourth Proportional to 89.61, 134.15 and 81.06

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Solution

The fourth proportional to 89.61, 134.15 and 81.06 is: 121.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.61 : 134.15 = 81.06 : x
  2. Step 2: Convert to fraction form
    89.61/134.15 = 81.06/x
  3. Step 3: Cross multiply
    89.61x = 134.15 × 81.06
  4. Step 4: Simplify right side
    89.61x = 10,874.24
  5. Step 5: Solve for x
    x = 10,874.24/89.61
  6. Step 6: Final answer
    x = 121.34

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.