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Finding the Fourth Proportional to 87.91, 121.31 and 49.09

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Solution

The fourth proportional to 87.91, 121.31 and 49.09 is: 67.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.91 : 121.31 = 49.09 : x
  2. Step 2: Convert to fraction form
    87.91/121.31 = 49.09/x
  3. Step 3: Cross multiply
    87.91x = 121.31 × 49.09
  4. Step 4: Simplify right side
    87.91x = 5,955.11
  5. Step 5: Solve for x
    x = 5,955.11/87.91
  6. Step 6: Final answer
    x = 67.74

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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.