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Finding the Fourth Proportional to 80.84, 120.65 and 77.60

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Solution

The fourth proportional to 80.84, 120.65 and 77.60 is: 115.81

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.84 : 120.65 = 77.60 : x
  2. Step 2: Convert to fraction form
    80.84/120.65 = 77.60/x
  3. Step 3: Cross multiply
    80.84x = 120.65 × 77.60
  4. Step 4: Simplify right side
    80.84x = 9,362.35
  5. Step 5: Solve for x
    x = 9,362.35/80.84
  6. Step 6: Final answer
    x = 115.81

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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.