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Finding the Fourth Proportional to 87.72, 121.19 and 77.37

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Solution

The fourth proportional to 87.72, 121.19 and 77.37 is: 106.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.72 : 121.19 = 77.37 : x
  2. Step 2: Convert to fraction form
    87.72/121.19 = 77.37/x
  3. Step 3: Cross multiply
    87.72x = 121.19 × 77.37
  4. Step 4: Simplify right side
    87.72x = 9,376.08
  5. Step 5: Solve for x
    x = 9,376.08/87.72
  6. Step 6: Final answer
    x = 106.89

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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.