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Finding the Fourth Proportional to 80.86, 120.70 and 77.82

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Solution

The fourth proportional to 80.86, 120.70 and 77.82 is: 116.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.86 : 120.70 = 77.82 : x
  2. Step 2: Convert to fraction form
    80.86/120.70 = 77.82/x
  3. Step 3: Cross multiply
    80.86x = 120.70 × 77.82
  4. Step 4: Simplify right side
    80.86x = 9,392.87
  5. Step 5: Solve for x
    x = 9,392.87/80.86
  6. Step 6: Final answer
    x = 116.16

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.