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Finding the Fourth Proportional to 89.16, 133.25 and 81.40

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Solution

The fourth proportional to 89.16, 133.25 and 81.40 is: 121.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.16 : 133.25 = 81.40 : x
  2. Step 2: Convert to fraction form
    89.16/133.25 = 81.40/x
  3. Step 3: Cross multiply
    89.16x = 133.25 × 81.40
  4. Step 4: Simplify right side
    89.16x = 10,846.55
  5. Step 5: Solve for x
    x = 10,846.55/89.16
  6. Step 6: Final answer
    x = 121.65

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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.