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Finding the Fourth Proportional to 79.89, 119.90 and 39.39

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Solution

The fourth proportional to 79.89, 119.90 and 39.39 is: 59.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    79.89 : 119.90 = 39.39 : x
  2. Step 2: Convert to fraction form
    79.89/119.90 = 39.39/x
  3. Step 3: Cross multiply
    79.89x = 119.90 × 39.39
  4. Step 4: Simplify right side
    79.89x = 4,722.86
  5. Step 5: Solve for x
    x = 4,722.86/79.89
  6. Step 6: Final answer
    x = 59.12

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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.