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Finding the Fourth Proportional to 80.70, 120.89 and 39.99

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Solution

The fourth proportional to 80.70, 120.89 and 39.99 is: 59.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    80.70 : 120.89 = 39.99 : x
  2. Step 2: Convert to fraction form
    80.70/120.89 = 39.99/x
  3. Step 3: Cross multiply
    80.70x = 120.89 × 39.99
  4. Step 4: Simplify right side
    80.70x = 4,834.94
  5. Step 5: Solve for x
    x = 4,834.94/80.70
  6. Step 6: Final answer
    x = 59.92

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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.