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Finding the Fourth Proportional to 89.69, 123.81 and 87.89

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Solution

The fourth proportional to 89.69, 123.81 and 87.89 is: 121.33

Step by Step Solution

  1. Step 1: Write the proportion equation
    89.69 : 123.81 = 87.89 : x
  2. Step 2: Convert to fraction form
    89.69/123.81 = 87.89/x
  3. Step 3: Cross multiply
    89.69x = 123.81 × 87.89
  4. Step 4: Simplify right side
    89.69x = 10,881.66
  5. Step 5: Solve for x
    x = 10,881.66/89.69
  6. Step 6: Final answer
    x = 121.33

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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.