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Finding the Fourth Proportional to 79.99, 119.85 and 39.31

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Solution

The fourth proportional to 79.99, 119.85 and 39.31 is: 58.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.99 : 119.85 = 39.31 : x
  2. Step 2: Convert to fraction form
    79.99/119.85 = 39.31/x
  3. Step 3: Cross multiply
    79.99x = 119.85 × 39.31
  4. Step 4: Simplify right side
    79.99x = 4,711.30
  5. Step 5: Solve for x
    x = 4,711.30/79.99
  6. Step 6: Final answer
    x = 58.90

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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.