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Finding the Fourth Proportional to 87.87, 121.40 and 69.69

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Solution

The fourth proportional to 87.87, 121.40 and 69.69 is: 96.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.87 : 121.40 = 69.69 : x
  2. Step 2: Convert to fraction form
    87.87/121.40 = 69.69/x
  3. Step 3: Cross multiply
    87.87x = 121.40 × 69.69
  4. Step 4: Simplify right side
    87.87x = 8,460.02
  5. Step 5: Solve for x
    x = 8,460.02/87.87
  6. Step 6: Final answer
    x = 96.28

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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.