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Finding the Fourth Proportional to 80.94, 120.54 and 78.78

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Solution

The fourth proportional to 80.94, 120.54 and 78.78 is: 117.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.94 : 120.54 = 78.78 : x
  2. Step 2: Convert to fraction form
    80.94/120.54 = 78.78/x
  3. Step 3: Cross multiply
    80.94x = 120.54 × 78.78
  4. Step 4: Simplify right side
    80.94x = 9,496.14
  5. Step 5: Solve for x
    x = 9,496.14/80.94
  6. Step 6: Final answer
    x = 117.32

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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.