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Finding the Fourth Proportional to 87.69, 120.65 and 80.49

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Solution

The fourth proportional to 87.69, 120.65 and 80.49 is: 110.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    87.69 : 120.65 = 80.49 : x
  2. Step 2: Convert to fraction form
    87.69/120.65 = 80.49/x
  3. Step 3: Cross multiply
    87.69x = 120.65 × 80.49
  4. Step 4: Simplify right side
    87.69x = 9,710.52
  5. Step 5: Solve for x
    x = 9,710.52/87.69
  6. Step 6: Final answer
    x = 110.74

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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.