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Finding the Fourth Proportional to 87.69, 131.33 and 74.78

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Solution

The fourth proportional to 87.69, 131.33 and 74.78 is: 111.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.69 : 131.33 = 74.78 : x
  2. Step 2: Convert to fraction form
    87.69/131.33 = 74.78/x
  3. Step 3: Cross multiply
    87.69x = 131.33 × 74.78
  4. Step 4: Simplify right side
    87.69x = 9,819.83
  5. Step 5: Solve for x
    x = 9,819.83/87.69
  6. Step 6: Final answer
    x = 111.98

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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.