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Finding the Fourth Proportional to 87.69, 121.05 and 54.99

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Solution

The fourth proportional to 87.69, 121.05 and 54.99 is: 75.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.69 : 121.05 = 54.99 : x
  2. Step 2: Convert to fraction form
    87.69/121.05 = 54.99/x
  3. Step 3: Cross multiply
    87.69x = 121.05 × 54.99
  4. Step 4: Simplify right side
    87.69x = 6,656.54
  5. Step 5: Solve for x
    x = 6,656.54/87.69
  6. Step 6: Final answer
    x = 75.91

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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.