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Finding the Fourth Proportional to 80.65, 120.87 and 39.99

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Solution

The fourth proportional to 80.65, 120.87 and 39.99 is: 59.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.65 : 120.87 = 39.99 : x
  2. Step 2: Convert to fraction form
    80.65/120.87 = 39.99/x
  3. Step 3: Cross multiply
    80.65x = 120.87 × 39.99
  4. Step 4: Simplify right side
    80.65x = 4,833.59
  5. Step 5: Solve for x
    x = 4,833.59/80.65
  6. Step 6: Final answer
    x = 59.93

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.