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Finding the Fourth Proportional to 80.91, 120.54 and 77.67

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Solution

The fourth proportional to 80.91, 120.54 and 77.67 is: 115.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.91 : 120.54 = 77.67 : x
  2. Step 2: Convert to fraction form
    80.91/120.54 = 77.67/x
  3. Step 3: Cross multiply
    80.91x = 120.54 × 77.67
  4. Step 4: Simplify right side
    80.91x = 9,362.63
  5. Step 5: Solve for x
    x = 9,362.63/80.91
  6. Step 6: Final answer
    x = 115.72

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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.