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Finding the Fourth Proportional to 87.81, 121.08 and 55.02

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Solution

The fourth proportional to 87.81, 121.08 and 55.02 is: 75.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.81 : 121.08 = 55.02 : x
  2. Step 2: Convert to fraction form
    87.81/121.08 = 55.02/x
  3. Step 3: Cross multiply
    87.81x = 121.08 × 55.02
  4. Step 4: Simplify right side
    87.81x = 6,661.82
  5. Step 5: Solve for x
    x = 6,661.82/87.81
  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.