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Finding the Fourth Proportional to 87.77, 121.07 and 55

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Solution

The fourth proportional to 87.77, 121.07 and 55 is: 75.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.77 : 121.07 = 55 : x
  2. Step 2: Convert to fraction form
    87.77/121.07 = 55/x
  3. Step 3: Cross multiply
    87.77x = 121.07 × 55
  4. Step 4: Simplify right side
    87.77x = 6,658.85
  5. Step 5: Solve for x
    x = 6,658.85/87.77
  6. Step 6: Final answer
    x = 75.87

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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.