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Finding the Fourth Proportional to 80.88, 120.78 and 78.96

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Solution

The fourth proportional to 80.88, 120.78 and 78.96 is: 117.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.88 : 120.78 = 78.96 : x
  2. Step 2: Convert to fraction form
    80.88/120.78 = 78.96/x
  3. Step 3: Cross multiply
    80.88x = 120.78 × 78.96
  4. Step 4: Simplify right side
    80.88x = 9,536.79
  5. Step 5: Solve for x
    x = 9,536.79/80.88
  6. Step 6: Final answer
    x = 117.91

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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.